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(^ ^ ^ r.. a TO ONf WHO HAS ALWAYS MANIFESTED THE KEENEST INTEREST IN MY PROFESSIONAL WORK, THIS VOLUME IS AFFECTIONATELY DEDICATED,— MY WIFE 16311 PREFACE In presenting this volume to working botanists the hope is indulged that it may also prove of service to engineers and especially to foresters. During its progress through the press various opportunities have been offered for testing not only the accuracy and value of the diagnoses for the recognition of woods about the identity of which there was some doubt, but also its general application to the elucidation of important questions relating to practical forestry ; and the fact that such a work is greatly needed at this time, and may materially assist in the development of modern forestry, has been strongly empha- sized. An important field for useful research may be found in an extension of the studies here indicated, not only with respect to exotic gymnosperms, but in their application to dicotyledonous woods, many of which present problems of great scientific interest and practical value. An effort has been made to keep the work up to date, espe- cially with respect to the treatment of fossil woods, but the author is only too conscious of many imperfections which it is hoped the application of the book to practical service may assist in making clear and ultimately removing. Montreal, Canada D. P. PENHALLOW CONTENTS PART I— ANATOMY Introduction .... J CHAPTER I. General Directions for th Preparation of Material and the Value of Particular Sections i^^ II. The Growth Ring: its structural features and relation to age ... 24 III. Tracheids: spiral, pitted, and resinous wood tracheids,— their structure and relation to development IV. Bordered Pits: their genesis, structural variations, distribution, and phylogenetic relations V. Medullary Rays : their morphology and kinds .78 VI. Medullary Rays (.ontinueJ) : ray tracheids,- their mon>hology and distribution „„ VII. Medullary Rays (f<,«//«;W): relations to development . . . . ,03 VIII. Wood Parenchyma : crystallogenous idioblasts and resin cells, — their structure and relations to classification ,00 IX. Re.sin Passages : their morphology I'^ X. Resin Passages {co»/i„u,d) : their distribution and relations to phy- logeny, and classification 20; vii viii ANATOMY OF THE GYMNOSPERMS PAbl Coniferales *'o Torreya 2'0 Taxus ai2 Thujopsis *IS Cryptomeria *|6 Podocarpus 216 Taxodium 217 Libocedrus *I9 Thuya 220 Sequoia *23 Cupressus 2*8 Cupressoxylon 238 Juniperus 244 Abies 253 Tsuga 265 Pseudotsuga 271 Larix 276 Picea 281 Pinus 291 Section I. Soft Pines 30S Section II. Hard Pines 3'8 Pityoxylon 34° Appendix A: Tables of Avvtomical Data 3S3 Appendix B: Volumes of Tracheids and Thickness ok Walls . . 358 Literature 3^2 Index 3^7 Plates 375 NORTH AMERICAN GYMNOSPERJViS Part I — Anatomy Part I— Anatomy INTRODUCTION The present work had its origin in 1880, in an attcmr-t to con- strue a system of classification for the North American Coniferje based upon the anatomy of the vascular cylinder of the t.iaturr stem. The fundamental idea was that such i classifica ion woula prove of great value in the identification of material used tor structural purposes, but investigations had not been carried very far when it became manifest that some such arrangement was imperatively demanded in other directions and for purposes of a more strictly scientific character. In entering upon the study of fossil plants it was recognized that the most fruitful source of reliable data must be found in the stem structure. At that time there was little in the way of an adequate basis for further study of this sort, inasmuch as the current diagnoses of the vascular structure were found in most cases to be singularly inadequate, and often so incorrect as to require extensive revisions. It was found furthermore that in order to reach correct conclusions in the case of stems which must often present marked structural alterations, arising through the influence of decay and other con- ditions attending fossiJ..'ntion in its various fi)rms. it was indis- pensable that there should be a trustworthy means of comparison with existing types, whereby sources of error arising from elimi- nated structures might be definitely excluded, and the ^ossil referred with certainty to its nearest relative. The original intention was therefore modified with a view to meeting the requirements of paleobotanical research. During the time these mvestigations have been in progress there has been much change m the views held by botanists respecting the significance of ana- tomical features as affording evidence of descent; and our own 4 ANATOMY OF THE GYMNOSPERMS studies brought forth facts which gave repeated emphasis of the most positive kind to the idea that questions of phylogeny cannot be settled either by the morphologist in the narrower sense or by the physiologist when acting independently, and that a proper historical point of view can be gained only when to such labors we join the data derival from a critical study of the stem structure in all its details. The original intention was to make a complete study of all the North American woods, comprising, as enumerated by Sargent in his report in the Tenth Census of the United States, some four hundred and nineteen species and varieties ; but the great impor- tance of the Coniferae from an economic point of view, their fre- quent representation in the fossil state, and their relatively more simple structure eventually led to their selection as the one group in which initial studies might be prosecuted with the most imme- diate and profitable results. While the North A i.. lean species constituted the original basis, various exotic species were added from time to time, with the result that our studies, as now com- pleted, comprise ninety-two species from North America, twenty- one species from Japan, and four species from Australasia. This extension has proved of great value, not only from a paleonto- logical ix)int of view but also because of the important bearing such exotic types have had in the solution of questions relating to descent. In determining the particular nature of the material to be dealt with in the prosecution of these studies several considerations of fundamental importance were kept in mind, among the more prominent of which we may consider the following. The economic application of wood involves the employment, solely, of the material which lies within the woody zone between the bark and the pith. It was therefore held that for the recogni- tion of timber or wood derived from constructions of any kind that these two latter regions of the stem would be worthless, and that a system should be devised which would, if possible, permit the recognition of the species apart from such structures. Experience has not only shown that this is possible, but that the characters INTRODUCTION embodied in the structure of the pith and barl< arc, in most cases, least definite, and therefore of minimum '.akje for tliffcrential purposes. Furthermore the structural variitions which may Ix; ussumed to arise in conformity with the getiend evolution of the species or genus are always most pronouncetl in the xylem struc- ture, in consequence of which the latter acquires exceptional value for purposes of relationship and phylogeny. Woody plants which are found in the fossil state often show a complete absence of pith structure, due to the operation of extended decay which may have been initiated before the tree or shrub ceased to live. Much more commonly fossil plants are devoid of bark. Instances are on record, as in the case of Juniperus virginiana from the Pleisto cene clays, in which the plant is so perfectly and hermetically sealed up as to permit of a perfect preservation of the kirk as well as of other portions of the stem, but such examples are com- paratively rare. More commonly the extended maceration and lecay to which plants are subjected before silicification or calci- fication occurs, involves a loosening and subsequent removal of the bark, especially when the tree is subjected to such mechanical action as is associated with its transport by water. It is therefore obvious that any system of classification which would serve the highest purposes for paleontological research must be wholly independent of both bark and the pith. Another consideration oi importance in this connection relates to regional differences of such a nature that different parts of the stem exhibit more or less striking variations of structural detail. As these will be dealt with somewhat in detail in a subsequent chapter, it will be sufficient for the present purpose to indicate that the characters upon which the generic and specific differentiations rest are essentially independent of location, and it therefore matters not whether the sample selected comes from a branch or the main stem, or whether it is derived from the top, bottom, center, or circumference of the latter, though as a matter of preference the wood of a mature stem would be selected as furnishing the best average conditions of structtirc, and therefore the greatest facility in determination. 6 ANATOMY OF THE GYMNOSPERMS Two objects have been helc' in view in the preparation of this work : (i) its application to the needs of the scientific botanist in prosecuting researches cither in recent or fossil forms, and (2) its adaptation to the requirements of the practical engineer who may be called upon to recognize material entering into the construction of bridges or other important works. While, there- fore, Part I deals primarily with the anatomy of the stem, dis- cussing such features as are essential to a correct knowledge and interpretation of the systematic portion, it also includes special chapters having a more or less direct bearing upon the practical utility of w ods, — such as may be found in those on the general mode of operation of fungus parasites, the durability of woods under different conditions, and the specific action of decay upon the tissues. Owing to the great extent of ground covered by the subject of timber diseases and the special methods to be employed for their control, and the fact that an adequate discus- sion of these important topics would extend the present work much beyond all reasonable limits, the reader is referred for the treatment of diseases to Tubeuf (72), and for methods of wood preservation to important papers by Flad (20) and Constable (10). If such treatment of the general subject serves to secure a wider constituency among those who are called upon to make large use of valuable woods, one of the larger aims of the present work will have been achieved. Part IT (3 based upon the details of Part I, and it relates exclusively to questions of classification and relationship. In attempting to construct a classification of the Coniferales upon the basis of the anatomical characters to be found in the woody portion of the stem, it appeared that there was little to be obtained from the work of previous investigators which could be employed as a satisfactory woiking basis, since the results recorded by Nordlinger, Hartig, Muller, and others, while of great impor- tance with respect to certain aspects of structure and afford- ing many important suggestions, had not been carried to that point where they could be reduced to any very great practical utility. A survey of the literature of the subject showed that INTRODUCTION y the study of a particiOar group of woods was not sufficiently exhaustive to permit of final inclusions, and that in many cases the dugno.scs were not drawn with sufficient attention to strict accuracy of statement and that regard for exhaustive deta.1 which would render them of the greatest value. In deal- ing with the structure of the wood for taxonomic purposes it has been found that the diagnosis must take cognizance of a wide range of detail, and that it must be most searching in Its character. This is a necessary result of the high degree of development of the organisms and the consequent differentia- tion of the structure along several lines of development It is a neglect of this fact in the past which appears to explain why previous investigators have failed to construct a system of cla,si. fication which would not only give some additional information respecting phylogeny, but which would at the same time permit of a satisfactory recognition of species and genera. Under these circumstances it appeared desirable to commence ./.- novo and in the first instance, make an exhaustive study of the anatomy of the wood, utilizing for purposes of classification such facts as might be obtained in this way. As a convenient starting point tor the discussion of relationships it was considered that none could be secured which would be better adapted to the purpose m view than the classification generally employed as based upon the external morphology of the vegetative organs and inflorescence. For this purpose I at first selected the then most recent and authoritative compilation relating to the North American Coniferales. as embodied in Professor Sargent's valu- able work on the woods of North America in the Tenth Census of the United States. To this were later added Sargent s Silva 0/ North America and ne sequence of Engler and Prantl con- ained m the Natur/ic/uu Pflanzcnfantilicn, as expressing the latest views c.i the subject. Assuming the typical character of the trees discussed by Sargent, it was held that any well-authenticated specimen of wood rom any such tree would also be typical, and in this way It would be possible to form a type series the structure of which ANATOMY OF TIIK f;N MNOSI'KHMS could bo discussetl with direct reference to the aKAiimcd rclati >n- ships based uium external i haractcrs. The nucleus of such a type scries was found in the Sr.rgcnt collection of woods derived from his work in connection with the Tenth Census. To this other specimens were added through the ccjrtesy of Professor Sargent and Mr. J. G. Jack of the Arnold Arboretum ; Dr. N. L. Britton of Columbia University, and now Director of fht New York Botanical Garden ; Mr. Morr's K. Jesup, President of the American Museum of Natural History; and Dr. B. E. Fernow, then Chief Forester of the United States Department of Agriculture, also to the late Baron P'erdinand von Mueller of Melbourne, Australia ; Sir VV. T. Thiselton-Dyer, late Director of the Royal Gardens, Kew; Mr. K. J. Maxwell of Montreal; and more recently Dr. E. C. Jeffrey of Harvard University ; to all of whom my grateful acknowledgments are due. Yet other speci- mens were obtained by personal collection or from trustworthy collectors whose reputation was sufficient guarantee for their authenticity. In this way it has been possible to include in the present list all of the North American species of the Coniferales as enumerated by Sargent in his Stha, with the exception of the recently described Juniperus flaccida. Present lack of material has also prevented me from making a critical study of Junijierus barbadcnsis in order to determine anatomically the identity wliich Sargent establishes on the basis of external characters ; while t e same comlitions have also barred a study of Juniperus scopulorum, Sargent, and Cupressus pygmaca, Sargent, with a view to determining their validity as distinct species. During the progress of the present studies a large amount of material came to hand from Japan and Australia. Its elabora- tion has afforded much information of the highest value, and it has been considered expedient to incorporate it in the present classification. With this material in hand the first step was to secure an accurate diagnosis of each species for each of the three sections usual in such cases, and when it is recalled that, as at present elaborated, this involved a critical study of twenty genera and one hiiiulrcd ami sixteen !*|)ccic», thus representing a total <»f three hundred and fortyeight sections, and that the diagn(.scs wc'" at first of a purely tentative character demanding frequent revision and extensi(.n, it will he understood that the enormous mass of detail involveil not only presented considerable diffi- culties but demanded the expenditure of much time and most patient and painstaking effort. The concurrent prosecution of IKiIeontological studies, in which a very critical means of differ- entiation was called for, because of structural djfccts arising from decay and other influences attendant upon the process, of fossilization, fortunately gave jusi the insight into the require- ments of critical diagnoses whic.i was required. It soon became clear that certain anatomical fer.tures stood forth with very great prominence, and that they could be successfully employed for the recognition of primary and secondary divisions of the group ; while other less prominent characters naturally fell into the categories of those which define genera and species. Upon this basis it was :>oon possible to difTerentiatc the various genera with acc dcy, as already set forth in previous publications (44). The systematic treatment cf the genera of the North American Coni- ferales then elaborated has been in constant and successful use for several years, as applied to the determination of both fossil and recent woods. Such experience has shown the classification to b ; iubstantially correct with respect to the accuracy of the diagnoses and the efficiency of the artificial key connected there- with. A few minor changes have been found necessary, anu these have been introduced in connection with the more recent revisions. Later experience, especially as derived from a more critical study of the anatomical details, has shown the need of a revision of the generic and specific sequences, us embodied in recently published papers (59) and now incorporated here. As it now stands, comparatively slight familiarity 'vilh the classifi- cation will enable one to refer most woods to their appropriate genera without hesitation. Thus Taxus, Torreya, and Pseudo- tsuga may be isolated at once by the single character which they possess in common, — tracheids with spirals, — while the last lO ANATOMY OF THE GYMNOSPERMS genus may be differentiated from the other two by the very simple, constant, and well-defined characteristics found in the presence of resin jiassagos and fusiform rays. Yet once more, Pseudotsuga, Larix, Picca, and Pinus fall into a natural group characterized by the i)resence of resin passages, and within the group differentiation of the individual genera follows on natural and simple lines. This is particularly true of Pseudotsuga and Pinus, in each of which the generic characters are so well defined as to leave no room for doubt ; while yet once more, Pinus may be subdivided into well-defined groups, or subgenera, representa- tive of the soft and hard pines. Abies and Tsuga are differen- tiated by the position of the resin cells and the character of the terminal walls of the ray cells ; Sequoia and Taxodium are sep- arated by the terminal walls of the ray cells, the character of the bordered pits on the lateral walls of the ray cells, and by the distribution of the resin cells ; Cupressus and Thuya are differ- entiated by the terminal walls of the ray cells, the distribution of the resin cells, the form of the pits on the lateral walls of the ray cells, and the form of the ray cells in tangential section. These principles are applicable to all other genera, and the key as now presented affords a trustworthy guide. For the species the question has been found to involve much greater difficulties, especially with reference to the genus Pinus, in which the number of essential elements increases greatly, while extreme variation also introduces a factor which adds much to the complexity of the problem. Two sources of error were early recognized as probable, — (i) incorrectly drawn or incomplete diagnoses, and (2) deviation from the selected type. The problem was to elaborate an analytical key of such com- pleteness as l;< eliminate any such errors, and then apply to it a test which would prove the extent of its accuracy, em- ploying the data so obtained in further corrections if necessary. For the purposes of a critical test I was furnished with care- fully selected material by Mr. Jack and Dr. Fernow to the ex- tent of eighty-five specimens representative of fourteen genera and forty-nine species. The specimens received from Mr. Jack INTRODUCTION , , represented a great variety of material in common use for struc- tural purposes. They included wood not only from the mature parts of the stem but also from the center of the trunk, em- bracing in some instances the structure of the pith and primary wood zone. For these reasons they possessed special value, inasmuch as they afforded an opportunity to determine the extent and nature of those structural variations which I had some reason to believe existed, as between the earlier and later growths of the stem. In transmitting his material Dr. Fernow stated that he had selected it " with reference to representing typical wood, and it was not taken from butt logs, top logs, nor branches or knots." It therefore represented exactly the problems which would be met with in every-day practice. The results of these tests as at first obtained were far from satisfactory. They clearly proved that the genera could be recog- nized with ease, but for the species they made it clear that there was need for a far more detailed diagnosis and differential key than was at first supposed to be necessary. More searching studies were made not only with respect to existing types but also as applied to fossil species from the Devonian to the Interglacial. These studies necessitated frequent recastings of diagnoses and corresponding alterations of the analytical key. They brought to light many important facts and relationships of the greatest value from a phylogenetic point of view as well as from the taxonomic, and they served to emphasize the fact that many of the more detailed structural features of the pines in particular, hitherto supposed to be of little or no value, were in reality of the greatest importance. A final application of the test specimens under the precise conditions which would obtain in ordinary practice showed a verification of 91.5 per cent for all genera and species. In this connection it may be of interest to note that the greatest sources of error were to be found in the second section of the genus Pinus, particularly in P. taeda, P. echinata, and P. glabra in the order given, whence it appears that these species stand out as the most variable of the entire Coniferales and, on the whole, the most difficult to determine. This is in precise accord with the 12 ANATOMY OF THE GYMNOSPERMS fact that these species are among the most highly specialized representatives of the entire phylum, and that they therefore stand as representatives of the highest order of development. The sources of error having been determined by such tests, cor- rections were applied to the key in such a way as to eliminate them, while the original diagnoses were further modified to meet the special requirements. It is manifestly impossible to construct a key capable of providing for all exceptional cases. These can only be met by the experience of the observer or by final refer- ence to and critical comparison with type specimens. But the experience so far gained justifies the belief that as now presented the key affords sufficient data for the recognition of species under all ordinary circumstances, and then" is no reason for hesitation in stating that it is fully as efficient in this respect as the keys usually employed for the determination of species on the basis of external morphology. In the employment of this classification the novice will en- counter certain practical difficulties the nature of some of which it may be well to indicate. In the genus Picea the differentiation of species is attended with more than the usual difficulty, and the same fact appears once more in the second division of the genus Pinus. This appears to be the result of a general advance toward a higher type of development, in consequence of which there is a more uniform distribution of similar characters among the various species. This feature also appears occasionally in other genera, especially in Juniperus, where it is not altogether easy to differentiate J. nana from J. communis, of which it has commonly been regarded as a varietal form. But J. rigida shows precisely the same relations to both of these, and I therefore prefer to retain the specific status of all three, though somewhat provisionally. In Pseudotsuga there is as much anatomical differ- ence between P. Douglasii and P. macrocarpa as there is between any well-Lnown and well-recognized species. There is therefore no reason for assigning the latter to a varietal position, and it should be given the status of a species, as correctly suggested by Sargent. In the genus Pinus, P. Murrayana cannot be regarded INTRODUCTION »3 as anatomically identical with P. contorta, as suggested by Sar- gent, for the same reasons as already applied to Pseudotsuga. Similarly P. Jeffreyi is a valid species and P. ponderosa scopu- lorum must be raised to the position of a species, while yet others fall into the same category. The sequence of genera and species, as well as the relations of the larger groups, is based upon the anatomical data presented in Part I, and it will be found to deviate considerably from most of the systems of classification now in use. In exhibiting this sequence, which appears abundantly justified from one point of view, it must nevertheless be carefully k. jit in mind that su^h an arrangement is in no sense regarded as fin;?'. At best it is a purely tentative measure, which shall ser\e as a contri- bution toward f final classification, and this latter can be com- pleted only when data from several sources are assembled and coordinated. As derived from our present studies the sequence of the Gymnosperms may be stated as in table on the following page. With respect to fossil forms an effort has been made to include all known North American species so far as they have been recognized through the structure of the wood alone. These have been included under their respective genera as now known for existing .species, and thus Cupressinoxylon » or Cupressoxylon are described under Cupressus, while Pinoxylon and Pityoxylon fall under Pinus. Unfortunately, in most cases, it is not possible t.. determine the structural characters with that detailed thorough- ness which is desirable, owing to the imperfect nature of the material, and it has therefore been found necessary to arrange the fossil species in a separate section of the genus and provide separate analytical keys. The very great difficulty of obtaining full differential characters necessitates reference to type speci- mens whenever a serious doubt arises. In several cases the > The genus Cupressinoxylon, as elsewhere shown, embraces what may prove upon revision of existing descriptions Sequoia in some cases and Cupressus m other cases, while according to Jeffrey's latest publications he employs the term for fossil Sequoias. Provisionally I prefer to include it under the 'genus Cupressus. 14 ANATOMY OF THE GYMNOSl'ERMS Class I. Cycadales. II. CORDAITALES. Order i. Cordaitae. Family i. Cordaitacea. Genus i. Cordaites. 2. Araucariinea:. 2. Araucariae. 1. Dammara. 2. Araucaria. III. GiNGKOALES. 3. Gingkoinex. 3. Gingkoaceac. 1. Gingko. IV. CONIFERALES. 4. Taxoidex. 4. Taxacea;. 1. Torreya. 2. Taxus. 5. Podocarpacea. I. Podocarpus. 5. Coniferae. 6. Taxodiineze. 1. Cr}'ptomeria. 2. Taxodium. 3. Sequoia. 7. Cupressineae. 1. Thujopsis. 2. Libocedrus. 3. Thuya. 4. Cupressus. 5. Juniperus. 8. Abietinex. 1. Abie.s. 2. Tsuga. 3. Pseudotsuga. 4. Larix. 5. Picea. 9. Pinoidex. I. Pinus. INTRODUCIION '5 diagnoses are given provisionally, since it is quite probable that in consequence of the fragmentary nature of the available mate- rial future studies will show several supposed species to be really identical with one another. In the case of a large number of fossil species it has not been found possible to obtain the type sections for descriptive purposes. Under these circumstances, although the original diagnoses differ materially from the general plan adopted, it has been thought best to incorporate them in the form of first publication, but with the name of the author appended. All of the illustrations emi-loyed in the preparation of the present work have been prepared from drawings and photographs by fhe author, and they may therefore be regarded as being par- ticularly applicable to the various questions brought under dis- cussion. Nearly all the text figures were first published in the American Xatiiralist, and are here reproduced through the cour- tesy of that journal. Some of the half-tone reproductions cf photomicrographs appeared in earlier papers relating to fossil and recent gymnosperms, while yet other' are introduced here for the first time. It has been impossible to introduce ail the illustrations which the clearest e.xposition might make desirable, owing to the limitations imposed by the expense of such a pro- ceeding ; but it is felt that the very generous allowance made by the publishers in this respect will suffice to render the leading facts of structure and relationship clear enough for our present purpose. rl CHAPTER I GENERAL DIRECTIONS AS TO THE PREPARATION OF MATERIAL AND THE VALUE OF PARTICULAR SECTIONS In determining the course to be followed in the preparation of material and its subsequent study, it is impossible to too strongly emphasize the fict that a correct and complete conception of the details of struct ire embraced in the vascular cylinder of the 3tem can be obtained only when the latter is studied from three points of view, or in three planes of section, — the transverse, the radial, and the tangential, the last two of which are of necessity also longitudinal. Although the importance of these three planes of section is well recognized by scientific botanists, it seems desirable to restate the fact in order to avoid any misconception which might otherwise arise through the minor importance attached to the longitudinal sections by recent authors (79, 350). Under cer- tain circumstances it sometimes happens that all three planes of section are not available, and the student is then compelled to rely upon two points of view or possibly even one for his con- clusions. In such an extremity it becomes possible to draw deductions from the material in hand as to the aspects of the structure presented by the remaining plane or planes of section, and so to reconstruct with approximate accuracy the entire fabric. But such a method should never be resorted to except when absolutely necessary, since to employ it under other cir- cumstances would involve a measure of doubt which would bring justifiable discredit upon the conclusions reached. The relative value of each section for such purposes will appear shortly. In proceeding to the study of a given wood too much stress cannot be placed upon the importance of very searching and accu- rate observations, especially if one is about to draw a diagnosis 16 GENERAL DIRECTIONS ,- of a new species. In making a diagnosis for comparison with that of a previously described species similar care is a neces- sity, particularly in the case of the different hard pines, where a comparatively slight deviation may involve one in considerable difficulty. Until one is thoroughly familiar with the course of procedure to be followed, and has an extensive knowledge of the anatomical details in all their varying aspects as characteristic of different genera and species, the only safe course to follow when attempting to identify a species, is to make a carefully written diagnosis in full. After this is done comparison with the key or with the supposed species may be made in detail A comparatively brief acquaintance with the systematic portion of this work will enable one to recognize most of the genera at sight, since the characters arc in most cases very clearly defined and easy of recognition ; but the same does not hold true of species, since these are defined by a larger number of characters which vary somewhat widely, and exceptional cases are of much greater frequency. Where there is a final doubt as to the iden- tity of a given species, the specimen should be compared with a type section or be submitted to an expert for decision. The transverse section exhibits in the main an end view of the various component elements. It should always be the first of the three to be examined, since it immediately permits a separa- tion of the genera into two great groups and affords suggestions of such a nature as to permit of economy of time at a later stage of the examination. It conveys a correct conception of the pres- ence or absence of certain structural features, such as resin passages, resin cells, or resin cysts and the presence or absence of thyloses; it affords the only accurate measure of regional dis- tribution and of the general character of the growth rings the relative volume and character of the spring and summer woods, and of the variations which distinguish the tracheids of those regions of growth. When elements have similar terminal aspects as the spiral and pitted tracheids, as well as wood parenchyma and parenchyma tracheids, the transverse section has no special value beyond that which is to be found in a recognition of I8 ANATOMY OF THE GYMNOSFKRMS regional distribution, although to a limited extent it is true that certain aspects of these elements may lead to correct inferences as to their structural features when displayed in other planes of section, whereby approximately correct data may be obtained even in the absence of longitudinal sections. This is particularly true with respect to the distribution of the resin i^assajjes, the relations of their longitudinal and radial distribution being such that where the one occurs the other may l)e inferred ; hence, if resin passages occur in the transverse section, we may conclude with certainty that they are also to be found in certain of the medullary rays, which will also present a fusiform aspect in tan- gential section.' The general character of the medullaiy ray is also displayed in this plane of section, but in its least important aspect. Although all the details of width and composition may be obtained much more accurately, and in some cases only from longitudinal sections, nevertheless the absence of these latter enables us to determine from the transverse section whether the rays are one or more seriate and if some of them contain resin passages. In order that the features thus indicated may be exhibited in their typical aspects, it is of the greatest importance that the plane of section be exactly at right angles to the axis of growth, otherwise the distortion of structure which necessarily results will not only make observation difficult, but it will serve to seriously impair the accuracy and value of any diagnosis which may be drawn. The radial section is also a longitudinal section the plane of which should exactly coincide with the radius of the stem. Any deviation from this position will cause the section to become more or less tangential, and just in proportion as it approaches this latter will its value diminish. In stems or branches more than five centimeters in diameter there should not be the least difficulty in securing the desired result, inasmuch as the abun- dance of material will admit of somewhat reckless cutting ; but in small branches of one centimeter or less, such as one must ' Certain exceptions to this law are to be met with in the case of fossil species. GENERAL DIRECTIONS ,g encounter in the case of fossil material, great care should be exercised in order to secure the few truly radial sections which the scanty material affords. When properly prepared such radial sections supply some of the most important data for diagnostic purposes. They furni.sh but little information as to regional dis- tribution, a feature which is of secondary importance in this case They do, however, furnish evidence of the highest value as to the form and structure of the trachcids, the character and extent of the transition zone, the regional distribution of the bordered pits and the various important details of their structure, size, and aggregation, the disposition and character of the spirals, and above all, it gives the only adequate knowledge of the medullary ray with respect to those features which are of the greatest value m the final differentiation of .species. It is true that some of the features of the ray may be inferred from a transverse and more particularly from a tangential section, but they cannot be utilized fully except in generic differentiations. The radial section gives a complete side view of the ray. e.xposing the entire structure in all Its details throughout the whole radial extent. It is from such data that we obtain our final decision respecting the separation of the first and second sections of the genus Pinus, the differen- tiation of Sequoia, Libocedrus. and Taxodium, the recognition of species wherever found, a differentiation of the Ta.xodiinea.- from the Cupressinerc ; and since it exposes the entire structure in all Its details, which are presented chiefly in side view, it permits us to determine their relatior-j to one another and to the activities of the plant as no other section can. As features of subordi- nate value the radial section completes our knowledge of the bordered pit, which it presents in section wherever these struc- tures he in the tangential walls, a distribution which may be more accurately ascertained in this plane of section than in the tangential, smce they are more certain to occur within the limits of a given field. For similar reasons the radial section affords the most convenient means of studying the longitudinal aspects of resin passages, resin cysts, resin cells, and crystallogenous idioblasts. 20 ANATOMY OF THK G\MNOSPERMS The tangential section, which is also a longitudinal one, is such as cuts a given radius at right angles, and it is . >)st completely such in all its parts when none of the included medullary rays are cut diagonally. This result is always possible in stems of large size from which typical tangential sections of several square centi- meters may be cut without difficulty ; but in small stems it often happens that only one or two sections of value can be obtained, since the nearer the plane of section approaches the center of the stem the more nearly does it approximate to a radial section. It follows from this that in many cases sections will have to be employed in which only a limited area exposes the typical struc- ture, all the rest being partially radial. With respect to the latter it should be pointed out that any deviation from a strictly tangen- tial plane will involve a distortion of the structure of the medul- lary ray, and inasmuch as the value of the latter for diagnostic purposes rests very largely upon the form of the ray cells, it will be evident that even a slight reduction of the angle from ninety degrees must introduce an alteration of form which renders the ray of no value. The chief value of the tangential section is thus seen to lie in its exposure of the extremities of the rays, the general composition and number of which may then be ascertained with accuracy. From this it is possible to infer the presento "f certain structures in the tranverse section, such as the resin passages, since as already pointed out there are very constant relations between the occurrence of such passages in the rays and in the longitudinal structure. Important exceptions to this otherwise general law are to be met with in certain resin cysts of traumatic origin among recent plants, and also in the case of certain extinct species. Thus Sequoia Burgessii does not exhibit resin passages in a transverse section, though they do occur and are characteristically developed in the medullary rays. Precisely similar structural conditions are to be found in Pity- oxylon chasense. From the recent studies of Jeffrey, however (25), we are led to the inference that such unusual relations, which at first seem to indicate some peculiar feature in develop- ment, may in reality be due to the fact that the longitudinal resin :1 OENERAI, DIRKCTIONS j., passages occur at such witlc intervals, or arc so grouped within narrow areas, that a given s|)ec imcn may show n.^ne of them in transverse section, although a very considerable area is examined. In a minor degree the tangential section is also useful but not necessary in extending our knowledge respecting the distribution of bordered pits in the tangential walls of the tracheids, but whenever such features are to be studied critically it will be necessary to provide two cntial sections for each species, one passing through the spring wood and the other through the summer wood. For the preparation of sections of fossil woods which are strongly silicified or calcified, or otherwise infiltrated with mineral matter, special apparatus for cutting and grinding is required, and this part of the work is best accomplished by intrusting it to one who has lined the necessary dexterity through long experience. For those fossil woods of comparatively recent deposits, such a!i the Pleistocene or later formations, which have undergone little or no modification by the infiltration of mineral matter, the methods applicable to woo One of the best of simple instruments is the table microtome made by Bausch and I,omb, but the knife used with this form of instrument should be a plane blade mounted in a heavy wooden handle of such form as to secure a perfectly firm grip. GENERAL DIRECTIONS ,j as some others. Under these requirements we may employ a stronji alcoholic solution of Bismarck brown which is actinically o|K.quc. Hy its use walls which are presented in section do not transmit enough light to affect the plate evei: after rather long exixjsures, while those walls which are presented in side view and are relatively of little volume transmit enough light to make a strong contrast. By using such process plates as the Imperial a well-taken negative will show sharply contrasting black and white and will bring out all the details. All of the photographs in the present work were taken in this way. After staining the sections should be passed into oil of cloves until thoroughly cleared, after which they shouU: k mounted in xylol balsam. I. f ii CHAPTER II THE GROUTH RING In proceeding to a study of the transverse section the first feature to which attention is naturally directed is the growth ring. These are either broad or tutrrow, variable or uniform, eccentric or regularly concentric according to their relative pro- portions in radial extent, the constancy of their radial volume, and their equal or unequal development at all points about a com- mon center. While a recognition of such features often serves an important purpose in confirming data from other sources, they are in reality of secondary importance and too much stress must not be laid upon them ; in fact, they may, if necessary, be ent= ' ' neglected in most cases. This clement of doubt is due to V that within a given transverse section of an entire sie. growth rings vary very greatly among themselves as the result of varying rates of growth induced by external con- ditions of soil and climate. These variations are of such a nature that, in general terms, the growth rings will have the greatest radial dimension in a young stem or at the top or toward the center of an old stem, while such dimension diminishes within the same stem radially outward, so that in the peripheral portion of a very old trunk the rings will be cither actually or relatively very narrow. This general rule is subject to many exceptions. In consequence of the suggestions furnished by this structural feature it is desirable to include its description in every diagnosis of a species, and we may therefore consider somewhat in detail its principal aspects of structure and variation. All of the North American Coniferales without exception, both fossil and recent, and also all of the Japanese species so far investigated, are characterized by well-defined growth rings. These regularly recurring zones of growth, arising through 24 iL^ i THE (IROWTH RING 25 alternating periods of physiological rest and activity, correspond very closely with annual periods, whence it is possible to utilize them in determining questions of age which may be ascertained in northern latitudes within an error not exceeding and usually much less than one per cent (53, i.._M. This law has been applied with success to the deteir.. nation of th ; probable age of certain blazes found in beech .ree in Carad... tracing them to the year 172 1 and their probab r r,ri rjn ,,t th-, hands of some of the early Franciscan missionaries (54, 350, and 55, 500) ; while Campbell has similarly applied it to a determination of the age of certain Sequoias and the years in which forest fires or other injuries were inflicted (9, 335). The chief sources of error in such estimates lie in the difficulty of clearly recognizing under all conditions the relation of a particular growth ring to a certain year, since it is a well-known fact that under peculiar conditions more than one ring may be formed in one season. Thus Penhallow has shown that while in northern latitudes there is an essential constancy in the relation of rings to annual periods, this constancy diminishes toward the equator with a tendency to the obliteration 01" the growth rings, whence it follows that at some intermediate point in latitude there will be more rings formed within a given period than there are years of age (5^3, 162). This is supported by the observed fact that in the state of New York the common red maple (Acer rubrum) has been known to form an average of three rings for each year of growth, while in Florida at least forty rings have been found in trees less than thirty years old. In such cases experience will soon mdicate to the observer that the demarcation between rmgs of successive years is much more pronounced than between those of the same year, directly corresponding to the duration an-.l intensity of the rest periods in each case, and from this It is possible to reduce the error from such a .source to a mini- mum. Thus De Bary has shown that such double growth rings as are referred to are the direct result of some disturbance of the normal course of growth for the season, such as may arise through the operation of frost, drought, insects, etc. (13, 514). 26 ANATOMY OF 11 li: OYMNOSPKRMS A concrete illustration of the conditions which would be likely to produce such a result is presented in a late frost which seri- ously affected vegetation in the neighborhood of Montreal m the sp.in- of 1902. On the 9th and 10th of May of that year a cold waveVssedover Montreal, and inflicted such serious losses upon early crops and effected so much damage to trees and shrubs as to excite much comment. At that time nearly all trees and shrubs were in tender leaf. Many were either in bloom or the flower buds -as in the horse-chestnut - were wel formed but not open. In such cases the new branches had already attained a considerable length, but in many of the later species, such as Catalpa. the English maple (Acer campestre), sumac (Rhus typhina), and the ash„ the leaf buds were not opened and no material injury resulted. In all of the earlier forms, however, the leaves and young branches were killed, and in the horse- chestnut and elder (Sambucus racemosa) recovery involved the formation of an entirely new set of organs ^ rom latent or adven- titious buds. In such cases it is altogether likely that an exami- nation of the wood for that year would show two rings of growth, between which the distinction might be expected to be less clearly defined than between those of successive years. Variations in the width and prominence of growth rings ot successive years are in some cases so marked that, were pieces of wood from the same stem to be examined without any knowl- ed-e of their previous relations, they might be regarded as re^csenting wholly different species. This is notably the case in the hard pines, such as P. palustris. P. cubensis, P. echmata. etc while it is also true of Pseudotsuga Douglasn, m which this feature has been critically studied. In a large cross section of this wood, embracing five hundred and thirty-eight growth rings, the latter were found to be disposed in well-defined zones, which vary greatly in width, while the component rings of cont^uous zones show well-marked differences in '"-f ^ J"^™^",/" ;"" structive example of such growth is given by Hartig (22. 40) m the case of the Tyrolean larch, taken from a height of a thou- sand meters and having an age of one hundred and nmety years THE CROWTH RING 27 though only nineteen centimeters in diameter. Further, within each zone (Pseudotsuga) the range of variation is narrower, and oftentimes the rings present a remarkable degree of uniformity. So well marked arc these differences that when a number of trees are examined it is possible to establish an exact correspondence of zones by means of the average dimensions of the component growth rings. These facts point with some force to the probable operation of similar, if not identical, conditions of growth over a somewhat extended period, while the periodicity of growth also suggests a corresponding periodicity in environmental conditions. It has elsewhere been shown (52, 35) that in the case of trees exhibiting four such zones the following results are obtainable : Variations of Zones and Growth Rings in Pseudotsuga Douglasii i ZUNK I ZUNB 2 Zone 3 ZUNR 4 No. 35 r Total width of zone, cm. . . • Number of rings I Average width of rings, mm. . 2.12 s 4.24 '5-77 73 2.16 16.48 141 1. 17 0.00 0 0.00 No. 2 r Total width of zone, cm. . . . •< Number of rings . . I Vverage width of rings, 0.00 0 0.00 11.95 SO 2.38 452 38 1. 19 0.00 0 0.00 No. 789 r Total width of zone, cm. . . . ■i Number of rings I Average width of rmgs, mm. . 17.07 39 438 2.85 10 2.85 4-77 27 1.70 1.36 14 0.97 No. 428 r Total width of zone, cm. . . ■j Number of rings I Average width of rings, mm. . 2.72 8 340 16.38 66 2.52 0.70 4 I-7S 0.00 0 0.00 No. 316 j- Total width of zone, cm. . . . •j ■ " -nber of rings ' .xverage width of rings, mm. . 16.28 33 4.96 4.42 '7 2.60 323 28 1.15 0.85 10 0.85 Totals, mm Averages, mm 16.95 4.24 12.51 2.50 6.96 «-39 1.82 0.91 28 ANATOMY OF THE GYMNOSPERMS The variations thus indicated are usually accompanied by a more or less marked alteration in the relative volumes of the spring and summer woods, in consequence of which the same tree may show regions of coarse-grained and fine-grained wood. Plate I exhibits the characteristic features of such fine-grained wood, and a comparison with plate 46 will serve to emphasize the deviation from the usual type of structure. Eccentricity of the growth ring is a feature more or less com- mon to all woods (31, 513). and it is determined by external con- ditions of light and warmth (22, 41 et seq.), but ordinarily such variations are not sufficiently marked to merit comment. In the genus Juniperus, however, eccentricity is developed to an un- usual extent, and it serves as a more or less distinguishing fea- ture. From the photograph presented in plate 2 i. 'be seen that the rings not infrequently coalesce on one side,Wi -c.n- ing great prominence as separate structures on the opposite side. A like eccentricity characterizes the genus Taxus. We are then to conclude that growth rings are a normal and constant feature in the stem structure of the Coniferales as a whole, and the same is also true of the Gingkoales so far as we know them through both fossil and recent examples of the genus Gingko. But the same law does not apply to the Cordaitales as a whole, and in this may be found one of the leading distinctions between these two groups. This is especially true of the genus Cordaites in which the " growth rings wnen present are obscure, rarely somewhat conspicuous," and even in the latter case they appear simply as regions of somewhat unequally variable density, dependent upon regional changes in the thickness of the tra- cheid walls and the volume of the lumen, the one region merging into tae other by somewhat gradual transitions and always without that sharply defined alteration of structure so charac- teristic of the growth rings in the Coniferales (plate i). In existing Araucarias the " growth rings are not determinable, or at most poorly defined," though De Bary (13, 513) cites the case of a specimen of A. excelsa grown in the open ground, which showed sixteen sharply defined growth rings, and Kraus has THE GROWTH RING 29 observed somewhat similar phenomena in the case of A. brasi- liana. Specimens coming under my own observation, but repre- senting growth which was completed in a conservatory, show that in A. excclsa and A. Cunninghamii the growth rings are either not determinable or at most very imperfectly defined ; while in A. Bidwillii they are only faintly defined by a slightly more open structure in the earliest spring wood. The same law holds tnie for fossil species in which it meets with only partial exceptions, as in A. Edvardianum. In Dammara the " growth rings are more or less clearly defined," approximating in this respect to what is found in the Coniferales, and between which and the typical Cordaitales they may be held to represent a transitional form. Apart from those conditions of internal tension which arise incidentally to the formation of dissimilar tissues, and which induce structural alterations, growth rings may be regarded in the main as a direct expression of the alternation of sharply defined growth and rest periods ; and since these in turn are cor- related with sharply defined seasonal changes, such as are com- mon to more northern latitudes, it becomes possible to utilize these facts in forming an approximate estimate of the general climatic conditions under which the tree must have developed. From this it is also possible to draw important inferences as to the climatic conditions which must have prevailed in t^.lier geological periods, as inc' :ated by the presence or absence and the specific charactei of growth rings in fossil woods, a conclu- sion which gains force from the relation which the formation of growth rings in Araucaria bears to climatic conditions, as already stated. Every growth ring presents two structurally dissimilar regions which correspond with different periods of activity, and it is the apposition of these in successive years which principally deter- mines the recognition of the growth ring. The initial growth of a given year arises at the earliest possible moment at which the cambium is capable of generating new tissue. The elements which thus arise are applied directly to the outer face of the growth rin-; for the preceding year. In the formation of such 30 ANATOMY OF THE (iYMNOSFERMS elements two important factors are involved. Owing to the peculiar conditions of growth attending their organization, they are formed under a minimum tension, in consequence of which they rapidly attain to relatively great size, and it is therefore found that the first tissue of the season is always most open. But this feature depends again upon the second factor. In con- sequence of the great excess of nutrition supplied during this period of growth, and the very rapid process of construction which follows, secondary growth of the walls is limited and these structures remain thin, while the lumens are correspondingly large. In transverse section such cells almost invariably show a greater length of the radial diameter, which is never less than the tangential. As growth advances there is a slight but pro- gressive change whereby the secondary development of the wall increases somewhat and becomes constantly thicker ; but the principal alteration occurs in the form of the cell in such manner that the radial and tangential diameters tend to equality. Such thill-walled structure is developed during the first four or si.x weeks of growth, and it is therefore designated as spring wood. Toward the end of the general growth period, which has elsewhere been shown to terminate by the second or third week of July for about ninety per cent of trees and shrubs in this latitude (80), the structural character of the ring is subject to more or less profound change as the rate of growth diminishes and the inter- nal tension of the tissues increases. The isodiametric form of the tracheid is then replaced by an extension of the tangential diameter and a shortening of the radial diameter, the latter pro- gressing more rapidly than the former. This alteration is of such a nature that in those tracheids which represent the last product of the season's growth the opposite tangential walls are closely approximated or even in actual contact, while the tangential dimension is sensibly increased as compared with tracheids of the same row in the spring wood. Coincident with these changes the secondary wall acquires an unusual prominence, and in many of the hard pines, as also in Pseudotsuga, it becomes so exces- sively thickened that the lumen is reduced to small dimensions THK (;ro\vhi ring 3« and not infrequently is almost obliterated. The snmuur xvood thus characterized is also distinguished by its greater hardness, which in the Douglas fir imparts an almost flinty character to the structure ; and commonly also, as exhibited in Pseudotsuga Douglisii, Pinus palustris, P. resinosa, etc., by a considerable amount of resinous matter, which, by reason of its definite color, estabUshes a more or less striking contrast between the two regions of growth. It is therefore obvious that 'he demarcation of the growth rings depends upon t'.e direct appLsition of spring and summer woods, each of which is characterized by special structural and other physical features. The transition from the spring to the summer wood is gradual when there is no sharply defined limitation of the two zones, but the one seems to merge into the other by a series of more or less insensible gradations. This is exemplified in its typical form in the Cordaitales, and among the Conifcrales it is a feature of the great majority of species. Under such circumstances the internal limits of the summer wood can be determined only approximately, and they are necessarily established where the greatest alteration of structure and color occur. Less freciuently the transition is abrupt, as in the hard pines, notably P. palustris, or in the Douglas fir (plate i). There is then a strong contrast between the two structural regions. A further variation of this relation is to be seen in those cases in which the somewhat grad- ual transition from the spring to the summer w\)(k1 is 'followed the next year by a corresponding change to the spring v.ood. This is of rare occurrence and is to be met with in only one case, — Pinus Torreyana, — in which also such double graduation seenis to arise only in the case of thick summer wood, since, when the latter is thin, the transition is abrupt. Rarely the summer wood exhibits a zonal development whereby it becomes doubled through the interposition of a zone of thin-wallcd and rather large-celled tissue. This finds its typical development in Taxodium distichum, of which it is a characteristic feature. It may also be met with occasionally among the higher Coniferales, especially among the hard pines. It ii a constant feature of taxonomic value. %t 1; 32 ANATOMY OF THE GYMNOSFERMS The relative volume of t spring and summer wood is subject to wide variation not onh between different genera and spe- cies but also as between iduals of the same species. While this depends in the first i icc upon inherent qualities, it is also dependent to a very larj, \tent upon conditions of growth. In Juniperus and some species of Cupressus, as also in Torreya and Taxus, the summer wood may constitute the bulk of the growth ring and render it impossible to determine where the spring wood ends. The opposite e.xtreme is to be met with in the genus Thuya and in many species of Cupressus, where the summer wood is reduced to from two to si.\ rows of tracheids, which are to be distinguished chiefly by their greater color and shorter radial diameters. The Douglas fir offers an excellent illustration of such variations within the limits of the species. This is shown by the following data, taken from five different trees, and also by plates i and 46. RklATIVE VC)LIT.MF.S OF SPRING AND .Sl'M.MF.K WoODS OKl.Wril Rl.Mis IN MlLLLMETHKh 5< Average Volume ofRing Slimmer Wood Spring Wood Ratios Average Volume Average Volume No. 2 . . I 1,950 0.891 1.059 1:1. 18 '• 428 . . •* 2.725 I. no ..6.S I : 1.45 " 789 • ■ 3 3-^SO 0-975 2.27s «:«-33 " 35" ■ \ r 4600 1.200 3-400 I : 2.83 " 35''' ■ ; "I '-455 0-383 1.072 1:2.79 4 3°97 0.791 2.236 1:2.81 " 3>6 5 5.100 0.950 4.150 « : 4-37 While it is thus evident that estimates of relative volume are of no great value for purposes of e.xact differentiation, they nevertheless do serve a useful purpose in some instances, and they should always 1^. taken into consideration in a diagnosis. CHAPTHR III TKACHEIDS In the Gymnosperms the woody structure of the stem is com- posed of 'ore or less fibrous elements to which the generic term trachcids may uC applied in conformity with the definition adopted by De Bary (13, 155), but whirh, for our present pur- poses, may be described as elements of indeterminate or more {jeneraliy of determinate length, of either a proscnchymatous or parenchymatous type, and ciiaracterized cliiefly by the presence of bordered pits. As such tracheids exhibit important varia- tions among themselves, chiefly with respect to form, distribu- tion, and structure, it is necessary to distinguish carefully between the various types entering into the structure of the woody axis. First of all it is possible to distinguish between those of the proscnchymatous type and those of the parenchymatous type, the differentiation being readily effected by means of the ex- ternal form. Those of the parenchymatous type are to be met with in either the medullary rays, when they may be described as ray trachcids, or they arise in series parallel with the prosen- chymatous elements with which they are therefore mingled as wood parenchyma, and they are to be dist .iguished as paren- chyma tracheids. A further discussion of these forms will be deferred until they can be brought into connection with the gen- eral structures of which they form characteristic features, while at this time our attention may be directed more particularly to the tracheids of the proscnchymatous type. The fibrous tra- cheids are of two kinds, spiral and pitted. The spiral tracheids are chiefly met with in the proto.xylem region of which they are characteristic and dominant elements and where they are of in- determinate length. Their spirals represent a secondary growth of the cell wall, and the latter is therefore devoid of pits 34 ANATOMY OF THE (lYMNOSPERMS except in transitional forms. Rarely the spiral trachcids are met with in the secondary wo, and by the uniform pre.sence of bor- dered pits of .secondary origin, chiefly on the radial walls; typical of the secondary wood in all genera. SPIRAL IKACIlhiUS 35 a Wood parent hy ma tracheiih, Ifsually xhorl, cylindrical cells with thin walln, tratiHVcrM terminal walls, and l)ordered pits. Confined to the higher Conifcrit. a. I'aienchyma intikeUs. Characteristic of the xylem of the higher Conifcrif.wiih which their general direction of growth coincides. Found in a.s.Hociation with thi- resin pas.sagcH. b. /iay traiheiiis. Characttri/cd . v their occurrence in the medullary rays with which their general direction of growth coincides. We may now proceed to a more detailed consideration of the structure and distribution of the trachcids thus classified. I Spiral Traciieids The spiral tracheids are so called because of certain narrow banris of secondary or tertiary growth which lie upon the inner face of the cell wall and take the form of definite spirals. These structures arc found to present great diversity in the fi rm of their transverse section, which, as shown many years since by De Bary (13, 1 56), may vary from elliptical or round-rectangular to an almost quadratic form. In general terms they may be de- scribed as ribbonlikc and localized tiiickenings of the cell wall, which are designed for the obvious purpose of strengthening the latter. While this purpose is not always a prominent feature in the Coniferas, it may nevertheless be recognized in the struc- ture of the protoxylem and it is conspicuously defined in those thin-walled elements to be met with among Pteridophytes or in the higher seed plants, notably in the spiral tracheids of Zea, in which there is a strong disproportion between the thickness of the initial wall and the volume of the cell. In more general terms, therefore, it may be looked for in succulent stems of vigorous growth rather than in those of a more woody character and slow growth ; or it appears more frequently in plants of a primitive type of organization than in those of a more advanced type, in which the elements have experienced a more general growth in thickness, and where, in con. /.lence, snecial contriv- ances for support are not demanded. I-'rom the standpoint of development, therefore, we may consider that the typical spiral 36 ANAIOMY OF IHK (lYMNOSPF.RMS of the primitive forms has been lost through replacement by or through its being merged by extension and fusion into a growth which is continuous between all points of the cell wall. The capacity for the formation of spirals is thus eliminated from the greater portion of the structure of the wood, though survivals are commonly met with in many of the higher seed plants, where they impart to the wcxkI more or less well defined characters of diagnostic value. This capacity is also lost mo.st completely in the greater number of the Cordaitales, Gingkoalcs, and Coni- ferales, — indeed, it may be said that for the secondary growth of the wall it is eventually lost in all species; but the tendency still survives, a fact made apparent by the observation that in certain species the tertiary layer of the wall invariably gives rise to such spirals, which then constitute definite and reliable diag- nostic features, while in other species they are only imix:rfectly formed, In all such cases the spirals are to be regarded as sur- vivals, — as the last phases of a tendency which elsewhere has become completely obliterated. The origin of the spirals may be traced to a localized second- ary growth of the cell wall. They con.stitute, in fact, the primi- tive form of the secondary wall which later becomes modified in accordance with altered conditions of growth in such way as to involve an obliteration of the spirals. Such changes are features of progressive development, in consequence of which it is generally true that such structures are always most promi- nent and abundant in the more primitive types, becoming more rare in plants ot a higher type of organization and development. Similar relations e.xist as between the primary and secondary wood of all known Gymnosperms, whence it is possible to recog- nize the general law that spiral tracheids are a feature of the protoxylem, to which region they are wholly confined in the Coniferales and Gingkoalcs, and almost strictly confined in the Cordaitales, being, with few exceptions among the higher Coniferales, wholly absent from the secondary x)Iem. The direction of the spirals is constant in most cases, being right-handed or ascending from right to left on the side nearest SI'IRAI, TRACHEIDS 37 the observer. Usually more than one spiral is ilevdopal in the same tracheid, l)ut it does not follow that the lull nunilar will be present at all pjints throughout the len^'th of the traihcicl. As between different genera and si)eties, the numlwr usually varies from one to four. This is much less than in the Angiosperms, where they may be as many as sixteen to twenty. Localization also occurs in such manner that the spirals often run in series, these latter being separated from one another by wider intervals, and as this relation is subject to somewhat wide variation within the same s|)ecies, it follows that it cannot be utilized success- tuUy for diagnostic purposes, although it is quite jxissible to rec- ognize and deHne and utilize the more general differences of distribution in the terms/^zf and distaul, miinerotis and approxi- mate. The variation in distribution above referred to is largely expressed in the fact that in the tracheids first formed in a sea- son's growth the spirals will always be most widely separated, while those which are formed later constitute a more compact series. This fact becomes prominent wherever such structures can he observed through a considerable radial extent of wood, and it is therefore particularly well shown in growth rings, though it may also be seen in the protoxylem region when the latter is of great radial extent, as in Cordaites. Thu.s in Taxus or Torreya or Psciidotsuga it may be seen that in passing from the earli- est spring tracheids to the last-formed summer wood there is a graduated condensation of the spirals whi. h agrees with the relativ, rate of development in ihe tracheids themselves. A similar variation is to be seen within the limits of an individual tracheid in such way that the spirals in tlu central region are more widely separated than those nearest the extremities. This has been adequately explained by De Bary (13, 157), who has shown the more distant coils to result from stretching of the walls during the period of very active development, but subse- quently to the formation of the spirals; while the condensed forms would be an expression of a .slower rate of growth in the cells or in special regions of them, in consequence of which the spirals more nearly retain their original relations to one another. 38 ANATOMY OF THE GYMNOSPERMS In the Coniferales the spirals throughout the entire extent of the protoxyleni structure are more or less distinct, though there is a more or less definite tendency to coalescence. Such a tendency becomes most pronounced in the lower Gymnospcrms, being especially well defined in the Cycadaceic ai.d the Corda- itaceac. In the former the spirals become approximated and blend in such a manner as to definitely reduce the areas devoid of secondary grow th, which then assume an elongated form ; and as this latter diminishes still further in length, the spirals are eventually replaced by a more general thickening of the wall through secondary growth, and definite pits arise. Such changes are progressive from the protoxylem radially outward through the entire extent of the secondary wood, so that there is a defi- nite series commencing internally with typically spiral elements and terminating outwardly with typically pitted elements, the two being connected by transitional forms. The same structural alteratidns may be seen in Cordaites, which offers a peculiarly mstructive illustration of the process because of the regularity with which the changes arise and the extent of the structure in which they lie. As these transformations which are completed within the transition zone are of great phylogenetic importance as well as of taxonomic interest, it will be necessary to trace them somewhat in detail as they appear in Cordaites Brandlingii. In the protoxylem region the structure is wholly composed of spiral tracheidb (plnte 3). In the successive radial development of new trache-- 's .her^ is a constant tendency to a more uni- form thickening of the cell wall by a secondary growth. This at first finds expression in the more compact arrangement of the spirals (plate 4), which later coalesce at various points, thus giving rise to more localized areas devoid of secondary thickening, and hence to a scalariform structure in which the general lines con- form more or less closely to the direction of the original spirals (plate 5). By a further modification the elongated, thin areas become converted into shorter, often isodiametric areas substan- tially by a process of division. A further tendency to general thickening of the walls causes the margins of the scalariform SPIRAL IRACHKIDS 39 structure to project from all sides and extend over 'he area of arrested growth as a lip which never completely closes at the center, where there is left a usually circular, sometimes oval or again lenticular or even oblong, opening, and in this manner the bordered pit is formed (plate 6). From the statements so far presented it may be correctly inferred that the structural alterations which arise within the transition zone are subject to great variations, whereby the change from spirals to bordered pits may arise very gradually through a broad, radial zone, as in Cordaites Brandlingii, or it may take place very abruptly, as in the modern Conifera:. The general tendency of such evidence is to show that with a higher type of organization there is a corresponding diminution in the transition zone and an increased abruptness in the structural alterations. The logical result of an extension of this process would be the reduction of the bordered pit to the condition of a simple pit, and ultimately to its complete obliteration. In the Conifernc the reduction of the bordered pit to a simple pit some- times occurs in the case of medullary rays or even in the case of tracheids with very thick walls, but it becomes most promi- nent in the Angiosperms, where it is a characteristic feature. Instances also occur in some of the hard pines, in which the pit is completely obliterated. This applies in particular to tracheids of the summer wood, the walls of which have become unusually thickened. The relations to which attention has. thus been directed some- what in detail have been expres.sed in more general terms by De Bary (13, 321) in the statement that, "Outside the primi- tive elements wider tracheae follow. Their development takes place successively, advancing from the inner edge of the bundle outwards, and, as a rule, at a time when the elongation of the entire part to which they belong is nearly at an end. The thickenings on their walls, therefore, have a successively denser arrangement ; dense spirals and annular tracheae, then reticu- lated and pitted tracheae, follow one another in succession from within outwards, with gradual transitions, or with the omission of ^- 40 ANATOMY OF THE GYMNOSPERMS one or the other intermediate form." It is probably a justifiable inference from the preceding facts that the relation which exists between the spiral tracheids of the protoxylem and the pitted tracheids of the secondary xylem in the Conifers is, in general terms and from the standpoint of development, the same as that exhibited between the lower and higher types of vascular plants. Inasmuch as specimens derived from fossil woods or from recent woods which have been employed for constructive pur- poses will almost invariably represent some portion of the sec ondary wood only, it follows that in all but exceptional cases the spiral structures so far considered will be entirely absent and in those few instances in which they may occur the de- termination that they belong to the protoxylem region can be made without difficulty. It is nevertheless true that in x few genera definite spirals are to be met with in the secondary wood structure of which they may then be characteristic features throughout the entire extent of the growth rings, or they may be more or less localized. Such spirals, which are obviously of an exceptional nature, are features in the development of the tertiary wall of the tracheid, and they are therefore character- istics of thick-walled elements. In all their essential character- istics of form and distribution they conform to the laws which gover . the spirals of the secondary wall, but they show a marked tendency to obliteration through degeneration in the relatively thicker walls. Thus in the genus Taxus or Torreya such spirals are common to all the tracheids of the growth ring, but in Larix, as a so in Pmus tneda, in both of which the walls are relatively thicker, the spirals are reduced to a vestigial form, being spo- radic and m the one case distant, while in the other case the individual spirals are only partially developed. This law is more exactly md specifically illustrated in P.seudotsuga, where there IS a sti contrast between the thin-walled spring wood and the very thick-walled summer wood. In the former the spirals are perfectly formed and constant, and they bear a very strong resemblance to what may be observed in the Taxace^ In the SPIRAL TRACHEIDS latter case, however, the spirals are either sporadic anH estigial P. Douglasu) or they are often almost completely obliterated P. macrocarpa). So well defined and constant are these relations that they serve as an important differen tial character for the genus. Tracheids with spirals developed in the tertiary layer of the wall are thus seen to be typical features of Taxus, Torreya, and Pseudotsuga, while they are also more or less distinctive features of Larix ameri- cana and Pinus tzeda. In all investigated species of Torreya there is a rather wide variation in the angle which the spirals make with the axis of growth, and this becomes most pronounced in T. califomica, which gives the lowest angle for any species of either Torreya or Taxus. Usually the spiral has an angle quite distinct from that of the lines of striation in the cell wall, but in Torreya taxifolia (fig. i) the two often coincide. The following will show the various details derived from the average of ten measurements for each species- Fig. I. Torreya TAXIFOLIA. Radial section showing spirals of tracheids and bordered pits, x 210 Average Angle Highest Angle Lowest Extreme Range Torreya nucifera . . Torreya taxifolia . . Torreya califomica . 70.5° 70.4 46.2 87.0° 770 63.0 57-0° 61.0 30.0 30-0° 16.0 330 Means 62.3° 75-7° 49-3° 26.3° In the genus Taxus (fig. 2) the spirals are rather close and in two, ^rely three, series. As in Torreya, they are typical throughout the spring wood, but with a pronounced tendency to obliteration m the summer wood. This tendency is subject to considerable 42 ANATOMY OF THE GYMNOSPERMS variation in different species. In T. canadensis the spirals are conspicuous throughout. In T. floridana they usually disappear in the later growth, and are wholly wanting in the two or three last-formed tracheids. In T. brevifolia they become very imper- fect in the outer summer wood and tend to disappear completely, only vestiges remaining in the last-formed tracheids. In T. cuspidata the spirals are generally absent from the summer wood, or when present are merely vestigial. The angle is somewhat greater — about 7 degrees — than in Torreya, and with respect to certain species this fact is apparent with- out special measurement. The four spe- cies appear to be paired off in such a way as to represent a mean difference of ,_j >-n I ^ p-^«« about 10.9 degrees as between T. cana- ]\i ' densis and T. floridana on the one hand. Fig. 2. Taxi s brevifolia. ^^^ "^^ brevifolia and T. cuspidata on Radial section showing the Other. In all cases the angles of b2:edM:s"':'':o^"' ^^^ ^P--^^'^ -- q-^e distinct from those of the lines of striation. The follow- ing details are based upon an average of ten determinations: Average Ancle Highest Angle IxtWEST Angle Extreme Range Mean op Two Tixus canadensis . . . Taxus floridana . . . Taxus brevifolia . . . Taxus cuspidata . . . 72.4° 78.4 63.0 66.1 88.0° 90.0 76.0 87.0 66.0° 72.0 55.0 45.0 22.0° 18.0 21.0 42.0 75-4 64.S Means 69.9° 85.2° S9-S° 25.7° A comparison of these results in detail emphasizes the fact that the distribution of the spirals, as between spring and sum- mer wood, is in direct harmony with the principles already SPIRAL TRACHEIDS 43 stated, and furthermore that the angles at which the spirals develop do not afford an adequate basis for generic differentia- tion. It is nevertheless possible to recognize subgeneric grr jps in such wise that in both genera a general line of division may be established at ;o degrees. In the case of Torreya californica the very low angle of 46.2 degrees may be regarded as a differ- ential character of specific value. In the genus Pseudotsuga spirals are confined to the tra- cheids of the spring wood. This has a partial exception in P. macrocarpa, in which vestigial spirals may be observed in the tracheids of the earlier summer wood. In this species the mean angle is 70 degrees, but the spirals are always character- ized by lack of prominence, they are often widely distant, and the somewhat extended areas within which they are wholly wanting or fragmentary suggests a process of obliteration. In P. Douglasii the average angle is 82 degrees ; the spirals are characterized by considerable prominence and they are also, on the whole, close. In P. miocena the angle ranges from 49 de- grees to 83 degrees, with a probable mean of about 65 degrees, from which it would seem likely that this .species occupies a position superior to that of P. macrocarpa, but this relation can- not be determined with certainty on account of the difficulty of ascertaining their distribution within the limits of the summer wood. In the genus as a whole the angle, the prominence of the spirals, and the closeness of the turns obviously possess well-defined differential value with respect to the limitations of the species. Among the higher genera of the Coniferre only two cases are known in which spirals occur, but in each the character is of a very sporadic nature. In Larix americana the spirals are fre- quently found in the summer wood, but they are .so inconstant m their occurrence and present such varying a.>pects that the angle cannot be determined. In Pinus taeda, where the walls of the summer tracheids are very thick, rudiments of spirals may sometimes be seen. Here also it is manifestly impossible to determine the angle. 44 ANATOMY OF THE GYMNOSPERMS Viewing these five genera collectively, their spirals conform fully, in their occurrence and relation to progressive develop- ment, to the general principles already stated, and especially as formulated by De Bary. They possess no differential value of generic rank with respect to Pinus and Larix, but they do have such value with res lect to Torreya and Taxus on the one hand and Pseudotsuga on the other, the differentiation resting upon their occurrence in the summer wood in the former and their exclusion from that region in the latter. Were any ques- tion to arise in this connection, it could be authoritatively decided by the definite association of resin passages and fusiform rays in Pseudotsuga. It only remains to determine how far such structural features may be employed as a basis upon which to determine the general phylogeny of the genera. Between Torreya and Taxus there is very little upon which to base conclusions respecting sequence in development, and it is apparent that both of these genera have attained to nearly the same level. Such differences as do exist, however, seem to point to the relatively though slightly inferior position of Torreya as indicated by (i) the smaller angle in that genus, and (2) the generally more compact spirals of Taxus. This view, so far as it possesses phylogenetic value, appears to confirm the conclusions respecting the relative positions of these two gen- era as already determined upon the basis of external morphology and stated by Eichler (15, 103). It is fairly clear, from the facts at hand, that all such spirals as are to be met with in the higher Coniferales are to be regarded as survivals of structures which gained greater prominence in a more primitive state of development of the organism. They do not, therefore, indicate simple parallelisms between plants occupying a similar horizon in the scale of development, but they rather direct attention to derivation from a common ancestry, and, as previously pointed out (59, 255), they lead us to the con- sideration that Torreya, Taxus, Pseudotsuga, Larix, and Pinus represent different branches of a general phylum, — undoubtedly also including other closely related genera in which the spirals PITIED TRACHEIDS 45 have been wholly obliterated, — which had its oigin at a point anterior even to such types as Cordaites, and therefore in a group probably represented by the Cycadofilices. Pitted Tracheids The pitted tracheids may be so distinguished because of the invariable presence of bordered pits upon their radial and, under some circumstances also, upon their tangential walls. Such pits belong to the secondary layer of the cell wall in all cases. In comparatively few instances such pits may be associated with spirals in the tertiary wall, when the two structures will be found so related that while the latter may overlap the former, the orifice always lies between the turns of the spirals (figs, i and 2). In their transverse aspect there is no feature which may be employed to distinguish the pitted from the spiral tracheids. In the longitudinal aspect the former differs from the more primi- tive forms of the spiral tracheid with respect to length and definite terminations in such way that the one is a wood cell while the other is a vessel, but between he two no sharp line of demarcation can be drawn, since, as already indicated, they pass the one into the other by insensible gradations. All tracheids exhibit the same structural features with respect to the development and composition of the wall, and as a knowl- edge of these is antecedent to a correct understanding of certain alterations which arise incidentally to growth and also to decay, It will be desirable to examine into the structure of the wall somewhat in detail. Assuming the primitive form of the cell to be that of a sphere, this form undergoes alteration in accordance with tiie immediate environment whereby growth first of all becomes excessive in one direction coincident with the axis of growth for the plant as a whole, while it remains practically equal in the r dial and tangential planes which cut the first at right angles. From this It follows that while in a longitudinal aspect the tracheid is always presented as a fibrous element with tapering extremities, 46 ANATOMY OF THE (iYMNOSPERMS in a transverse section it approximates more nearly to the primi- tive form and thereby exhibits a hexagonal outline as directly derived from the circular by mutual compression of contiguous elements. As the woody elements arise by division, their tend- ency at first is to assume the spherical form ; hence they split away from one another. But such separation is never fully com- pleted ; in fact, it is never developed to any marked extent in woody tissues and it remains localized. The separation is usu- ally confined to the angles of the tracheids, and it results in the formation of intercellular spaces, which therefore originate schi- zogenous:', (fig. 3). In the subse- quent uiodification of the wall by secondary growth these spaces, when not too large, are com- monly obliterated by infiltration. The presence of such intercellu- lar spaces always emphasizes the fact that what appears as a single membrane is in reality a double wall, one half of which belongs to each of the adjacent cavil In the secondary growth of the wall new layers are laid down S.V). Fig. 3. PSEUDOTSUGA DOUGLASII. Transverse section showing the struc- ture of the cell wall: p.w., primary wall; J.70., secondary wall ; /.?ses a few examples may be selected. Thus in all three '^ investigated species of Araucarb the ratio of the walls- spri-i^ to summer wood is I : I, a relation which exactly . >< p , with the absence of growth rings. In Juniperus vir^ji i.u,.i th. ratio is i : 2 ; in Cryi>. tomcria jaix)nica it is 1:4; in Isu - Si lx>ldii it is 1:5. On the other hand, the same sfK'ciesj '.. \i\' t two ratios as deter- mined by the peculiar condition! .,' ei.u'-t >, .ider which the growth has been formed. '! u - n Tax 1 . anadensis we may 4.fc 8 2.4 *'^^'*^ 4'8J = '♦^ '*' '" ^"^ Lp '' f ^ "^ «*; and in Libo- M- \Mn!o, therefore, it is 4.8 cedrus decurrens we may get 1.4 obvious that there are certain ratio differences between the walls of these two structural regions, -- differences which are more or less directly associated with sjxicics, —and while such differences may be of some value in tonfirming conclusions derived from other data, they are not of such a nature as to permit the formu- lation of a general law applicable to species in such a way as to establish a precise differentiation, since variation arises within the same species as a result of different internal and external conditions of growth, such as tension, soil, and climate, the lat- ter being influenced by situation and exposure. In many cases, where the actual thickness of the walls is the same, the apparent thickness will vary considerably. This is directly attributable to differences in the transverse volume of the tracheid, whereby the spring tracheid, from its greater size, will have a wall rela- tively thinner, and thus apparently thinner than that of the summer wood. Our investigations show that for twenty genera and one hundred and fourteen species the mean ratio is 1:2.12. The following summary for genera may be consulted in this connection : I'llTLD IkACHKlUS Tahik Of Ratios rou the Tracheiu Walls — Gknr 5i KA VoiiiMI .,r TR*<'Miti>, _ I 8lMH*K T.r •.KMlwCi "''""^""•'I'WaIH, L, „„ W.».i.mTK.vv,,„i Sr».-..i TO Slmmhi. '*"•»"'•"''""" ttKTHiN ^»«»» Wi«m I'""' AviiAuar Danimara Arauiukria (•iiigko I'lrreya i .ixus . ThujopMS Cryptoiii^ria Podocarpus Taxodium Ubocednu Thuya . . Se()uoia . Cupressus Juniperus Abies . . Tsuga . . Pseiidotsuga I^rix . . I'icea . . f'inus . . (■rand average I: 1^ I :i.lO 1:3.64 I : 1.62 I 1.67 'I 13 1:1.68 I : 2.01 1:1.25 1:2.60 1 :2.26 1:2.51 I :l.98 1:2.24 ':2-3S ' '-97 -3' 2.76 2.12 1.98 1:1.66 I : 1.00 '•'33 1 : 1.99 1 : 1.56 I :2.S0 I 4-00 • : '43 ■ : J.OO I 3 I 3 4 I I I I 1 :1.9s •1:1.70-1 l«:3-43J I I : 2.88 3 1:2.75 2 1:1.71 y I : 1.41 II 1:2.27 II i:3.or 5 I : 2.95 2 I : 2.86 4 I : 2.27 9 1:1.97 41 1 :2.I2 114 Variations in the transverse volume of the trachcid as ex- prcs.sod in square microns constitute the most prominent feature of any tran.s crse sc* tion. They are expressed most conspicuously between thv .spring and summer woods, and thex are due to the sanu causes which operate in the formation of the rin^,^ itself. Their relations are such that the earliest spring tracheids are alwrivs of greatest volume, but there is a progressive diminution radially outward at a somewhat uniform rate. At a certain point in radial develonment. however, there wul usiiall) ix found a some- what more m.-.^ied alteration, which in specific cases becom. most pronounced — Pinus palustris - and results in an abrupt tran.siiion from one zone to the other. In other cases —Tax-as M 52 ANATOMY OF THE GYMNOSPERMS and Torreya (plates 20 and 22) — the transition is so gradual that it is often difficult or impossible to establish the exact boundary between the spring and summer woods. Such dimi- nution in volume is accompanied by alteration of the two axes in such a manner that the tangential is steadily lengthened whUe the radial is correspondingly shortened. It is, therefore, commonly found that in the last-formed cells of the season the tangential diameter is somewhat longer in accommodation to the increased circumference of the zone, while the radial diameter is so shortened that the opposite walls are closely approximated or even in direct contact. The relative volume of the spring and summer tracheids is subject to somewhat wide variation within the limits of the genera, being in the ratio of i : i.io for Araucaria, where there is practically no distinction of the two zones, and of i : 3.64 in Gingko, where there is a correspondingly sharp definition. The mean ratio for twenty genera, represented by 1 14 species, is I : I.9S- Within species limits similar variations arise, the most marked extremes being represented by Sequoia and Juniperus In the former case the ratio varies from i : 1.77 in S. gigantea to r : 3.26 in S. sempervirens. In the latter genus the variation lies between i : 1.33 in J. conjugens and i : 4.4 in J. sabina A somewhat extended study of the Douglas fir has given an oppor- tunity to examine these differences with respect to a somewhat wide range of individuals. Thus in seven specimens taken with- out special selection, the following values are found : . r. 1:1.91 2. I : 2.83 3- 1:1.14 4- ' : 3.23 S- I :2.io 6. 1:1.92 7- 1:2.14 8. 1:2.50 9- : 1.70 10. : 2.6f: : 1.91 > : 2.83 I ^^g'O"^ variations in tlie same specimen. Regional variations in the same .specimen. Regional variations in the same specimen. RESINOUS TRACHEIDS The mean ratio for all these specimens is , : 2.2,, which very closely approximates to that for P. macrocarpa (r : 2.4,). and it shows that the spring tracheid is normally twice the vo ume o the summer trache.d. But such a ratio is subject to importan exceptions w.thm the limits of the individual. Thus the^ate for I and 2 relate to regional differences in the same specimen and the same as also true c^ 5 and 6, and 9 and ro. It^ there! ore obvious that such variations are in no sense of specific value for diagnostic purposes, since they are often as widely divergent withm the hmits of the species as between different spedes bemg determined by peculiar conditions of growth. Inasmuch as v^ria ions m the relative volume of the tracheids is a feature o he density of the wood as a whole, it may be supposed to bea a certain j^lat.on to the strength of material and so to the value of the wood for constructive purposes, but this has been shown not to be the case (52, 39). Resinous Tracheids In Araucaria excelsa a transverse section shows more or less numerous elements containing resin. These are not to be dis- tinguished in their general structure from the surrounding tra- chcds. and they are to be recogi.ized solely by their contents which are usually somewhat prominent. Their distribution is characteristic. They occur in small, scattered groups, or more commonly in rows one or two elements wide, parallel with the medullary rays and in immediate contact with them on each side. When the plane of section passes near the po.sition of apparently terminal walls, the latter are cut through in various ways but they never exhibit any structural features, and they are therefore ,n no way comparable with the terminal walls of he wood-parenchyma cells. In a radial section these elements are seen to be long and fusiform, exactly resembling the wood tracheids except for reddish-bro^vn, transverse plates which occur ether close to or exactly opposite a medullary ray, -a posi- t.on which IS more clearly seen in a tangential section (fig 4) ^ : iii i ■ 54 ANATOMY OF THE GYMNOSPERMS The dark plates closely resemble Sanio's bands, for which they might very readily be mistaken upon casual observation, or they might likewise be mistaken for terminal and unpitted walls. In Dammara australis these features are presented in their typ- ical form. The transverse section shows such elements to be numerous and dis- posed in radial rows on each side of the medullary ray (fig. 5). In a radial section they present the same fibrous and fusiform charac- ter as in A u- caria, but, in addition, the wall usually experi- ences a marked increase in sec- ondary growth within the region exactly opposite a ray (fig. 6). This fea- ture is also prominent in the transverse section (fig. 5). Such local increase in thickness always arises in adjacent cells in such a way that the more strongly thickened regions are exactly opposite, and they serve to constrict the cell cavity gradually from above and below, in such manner as to leave a channel about half the usual width of the cell cavity, which gradually widens upward and downward (fig. 6). It is at the position of maximum constriction that we find a transverse plate of variable thickness, but always of a reddish-brown color. These plates are always thinnest in their central region, and they may be of uniform thickness for the greater part of their extent. Fig. 4. Dammara austra- lis. Tangential section showing the relation of the resin plates and the medul- lary ray, and a fractured plate (r./.). x 225 Fig. J. Da.mmara austra- l.is. Transverse section showing the ' isposition of the resinous tracheids on opposiie sides of the med- ullary ray at r.t. x 300 RESINOUS TRACHEIDS 55 At the region of contact with the trachcid wall they become thicker and thereby attain a vertical distribution to an extent four or five times greater than the general thickness. At such position also there is a somewhat clear differentiation between the plate and the wall of cellulose in point of color. Such plates show absolutely nothing of the nature of pits, and they are in no sense comparable with the terminal walls of the wood-parenchyma cells, except in form and position (fig. 6). The peculiar position of these plates, their resinous color, and their simulation of both Sanio's bands and terminal walls excited a suspicion as to their true nature, and led to the belief that they might not be structural features at all. They were there- fore subjected to a series of care- ful tests to determine (i) if they were structural, (2) if they were resinous, and (3), if the latter, to what extent. It was recalled in this connection that, although f'evoid of any special secretory reservoirs in the wood, Dammara is nevertheless well known for its production of the resin known as kauri or gum dammar. It was sus- pected that the plates might be local deposits of resin, and they were therefore brought into direct comparison with gum dammar, the characteristics of which are well known and described by VVittstein (77, 63). Tests were applied to thin radial and tan- gential sections, employing for this purpose (i) various essential and fixed oils, (2) ether, (3) alcohol, (4) ammonia, (5) potassium hydrate in ij per cent solution, and (6) concentrated cupric acetate. The plates were found to be very refractory with re- spect to all these reagents, and in all cases no change was to be observed, even after the action had extended over a period of several weeks, except partially in the case of ether and Fig. 6. Dammara australis. Radial section siiowing the local thickening of the tracheid wall, and the occur- rence of resin plates (r./.) opposite a medullary ray. x 225 %i 56 ANATOMY OF THE GYMNOSPERMS r/>. alcohol, and completely in the case of potassium hydrate. In the ether reaction there did appear to be a certain diminution in volume, apparently tlirough solution, when the reagent was first applied, but after that there was no further alteration. The application of alcohol, both in the hot and in the cold, showed that while the resiu contained in the medullary rays was all dissolved, the plates were only partially affected. The reaction of the reagent was chiefly manifested in the development of strong curvature, often accompanied by fracture (fig. 4, r.p). This was evidently due to an increase in volume as the first tend- ency toward solution, and it gave the first definite evidence that the plates could not be of a cellulose character. Beyond this no further change was brought about, even after several weeks of action. The potassium hy- r/> \ drate gave the most positive results. At first there was no apparent change, but after an interval of about ten days or two weeks the plates were found to have completely dis- F1G.7. Dammara AusTRALis. Radial appeared, leaving a perfectly section showing the origin of the resin , , , • ., ,. . plates (r./>.). x 225 ^^^^^ Channel m the cell cavity. A further proof of the resinous character of these plates is to be found in the ruptures which they not infrequently exhibit (fig. 4, r./>.), and in the various developmental stages which may be observed without difficulty (fig. 7). These show that the resin gathers locally upon the inner face of the tracheid wall, and as its volume increases it projects from all sides toward the center, where it coalesces to form a continuous and imperforate septum. The facts thus obtained prove most conclusively that the plates are not cellu- lose, and although immersion in concentrated cupric acetate for eight weeks failed to develop the characteristic reaction, they point to the idea that the plates are probably resinous. The con- clusion is probably justifiable that they consist of gum dammar, RESINOUS TRACHEIDS 57 which they closely resemble in many of their reactions, but of a highly refractory and modified character. The same evidence also conclusively shows that the cells in which the plates are devel- oped are normal wood tracheids and not wood parenchyma, which IS altogether unknown in any of the Cordaitales. Any transverse section of the wood of Cordaites will show these resinous plates to be present, usually in much larger numbers than in either Dammara or Araucaria. and they exhibit the same features in dis- tribution (plate 12). Compare also plates 14 and 16 We are naturally led to ask. What is the purpose of these resin pbtes? The peculiar form in which the resin is deposited and the particular location of the plates points with much force to their connection with some functional activity, since if it were simply a question of the storage of secreted products, the latter would hardly be disposed as found, but rather after the manner common to so many of the Cupressine^; and this suggestion gams strength from the fact that with respect to the peculiar form of the resin masses as well as their location in the tissue the Cordaitales are peculiar among the Gymnosperms. No exact comparison can be established with other plants, and it is diffi- cult to suggest an adequate explanation. One thing does seem clear, however, and that is that since these plates are of an impervious nature and developed in some cases, at least, in con- nection with a special constriction of the tracheid cavity, they offer and possibly are specially designed to afford a definite obstruction to circulation in a vertical direction. In this sense they may be designed to serve the same general purpose that is accomplished by the development of thyloses in the vessels of the Angiosperms or in the resin passages of the higher Coniferales It IS therefore possible that they may be connected in some way, not at present clear, with a more complete restriction of the circulation to a horizontal direction, and particularly through the medium of the medullary rays as specialized channels for that purpose. Among existing Gymnosperms resinous tracheids are almost exclusively confined to Dammara and Araucaria, though It IS a noteworthy fact that similar structures occur rarely 'i\ 58 ANATOMY OF THE GYMNOSPERMS among the higher Coniferales. In the genus Abies they are prom- inent features in both A. Fraseri and A. grandis. In the former a transverse section shows them to be prominent and scattering through the summer wood, more rarely in the spring wood ; while in the radial section the resin is seen to be massive in the sum- mer wood, forming a peripheral layer in the spring wood. In A. grandis the resin is usually more abundant, but otherwise the features are the same. The taxonomic value of the resinous tracheids applies exclu- sively to the Cordaitales, where they are of ordinal value, though in Dammara and Araucaria they may also become of specific value. In Abies they are so sporadic and present so little con- stancy as to be of no value. From a phylogenetic point of view it is possible to determine the position which they occupy in the general scale of develop- ment, and so to utilize them in determining the position of plants in which they may occur. That they are met with in their most characteristic form almost exclusively in one of the most ancient, as also in one of the relatively primitive, groups of Gymnosperms points with force to the idea of their being also a primitive form of the secretory reservoir. This view is greatly strengthened by the fact that in such plants there are no special secretory reser- voirs such as may be met with in the higher Coniferae, nor do we even find specialized wood-parenchyma cells devoted to such purpose. In this sense the sequence of the resin-producing struc- tures would be (i) resinous tracheids, (2) resin cells, (3) resin cysts, (4) resin passages. The relation of such a sequence to the general phylogeny would be that, since resinous tracheids appear in a sporadic form in Abies and thereby represent a limited sur- vival of a primitive character, the Coniferales have a common origin with the Cordaitales, which, developing as a lateral member of the main phylum, has retained this feature as an essential characteristic while it has disappeared almost completely from the main line of descent. Such obliteration is fully expressed in the Gingkoales, which have also been developed as an offshoot from the parent stem. CHAPTER IV BORDERED PITS In a preceding chapter it has been shown how the bordered pit originates in the spiral structure of the protoxylem through a more general and continuous development of the secondary layer of the cell wall. We are now concerned with an inquiry into the detailed structure of these markings, their variations under different conditions of growth and situation, and their relations to taxonomy as well as to phylogeny. It has been seen that in the genesis of the bordered pit the bands of adjacent spirals or the bars of a scalariform structure generally enlarge toward one another so that the intervening area contracts about a common center, but the edges never com- pletely meet, so that a pit is left at the central point. In such contraction, however, the secondary wall is not joined to the pri- mary, but is free and springs from it as an arch which has a circular outline and a central orifice (fig. 8). As such pits are always paired on opposite sides of the primary wall, the entire structure, when seen in tangential section, is lenticular in form (fig. II), with a membrane traversing the central plane and two openings opposite to one another at the extremities of the minor axis. From this it is obvious that the pit as usually seen is a double structure which does not at first present a direct opening from one tracheid cavity to the other, for so long as the tracheids are growing or the protoplasm is present communication between adjacent tracheids is cut off by the primary wall, which consti- tutes a closing or /// membrane. By a subsequent change in this latter it may eventually become displaced from its central posi- tion and then lie against one of the arches. Under such circum- stances it is often not readily discernible, and the pit apnears as if the primary wall had been obliterated within its limits. In the 59 6o ANATOMY OF THE GYMNOSPERMS last instance, when the active protoplasm is withdrawn and the cell passes into a permanent condition, the membrane disappears, and the pit then forms a lenticular cavity in the line of the cell •.vail, which opens into adjacent tracheids. This is the appearance presented by all fully developed wood of the Coniferje. The obvious purpose of such pits is to provide channels of communi- cation between adjacent tracheids which would otherwise be com- pletely isolated by the impervious nature of the secondary wall. This fact serves to explain the situation in which such pits occur. Radial walls. The characteristic situation of the bordered pits is on the radial walls, where, as was shown many years since (13, i6o), " the pits of contiguous tracheids always correspond to one another in such a way that on each limiting surface all the cavities of the pits of one fit exactly over those of the other. The plano-convex cavities are thus applied to one another in pairs so as to form the lens-shaped pit cavities," as seen in tangential section. But on surfaces abutting on elements of another order, e.g. parenchyma cells, the bordered pits of the tracheids corre- spond to nonbordered pits or else are opposite an unpitted wall. Four typical variations of the bordered pits may be recognized, — (i) the multiseriate, when they are disposed in any number of rows more than two, (2) the two-seriate, (3) the one-seriate with occasional pairs of pits, and (4) the strictly one-seriate. The general sequence thus presented will be found to be in direct accord with the evolution of higher types of structure and organization. The most primitive type of Gymnosperm presenting a multi- seriate arrangement is the genus Cordaites. Among eleven species of this genus which have been critically studied within recent years (45) there is a general agreement in the constancy of this character which thereby becomes of generic Vf.!i)e. In all the species the pits are disposed in such a compact manner throughout the entire extent of the tracheid as to present a hexagonal outline. In Cordaites acadianum they are two- to five- seriate (plate 7). In other species they vary from two-seriate in C. hamiltonense and C. Newl uxyi (plate 8) to occasionally BORDERED PITS 6i four-seriate in C. Clarkei. In the majority of species the rows are not constant, but show a varying number from one to three or two to five, this variation being exhibited by adjacent tracheids m accordance with the variation of the latter in radial diameter- and viewmg this distribution as a whole, it cannot be doubted that It represents corresponding differences in development. One of the most striking features of the genus is to be met with in C Newberryi (plate 8), which is unique in the segregation of the pits into groups of six to thirteen. In Araucarioxylon (28. 614). while conforming to the char- acteristic form and compact arrangement presented in Cordaites the pits exhibit far less constancy in their serial arrangement,' and in this respect they are at once comparable with those of the existing Araucarias. Among the latter A. Cunninghamii shows a one- to three-seriate disposition, A. excelsa is one- to two-seriate while A. Bidwillii is strictly one seriate. All of the extinct species as comprised m the genus Araucarioxylon not only show similar variations, but such variations are found to cover a much wider range. A comparison of all the species, both recent and extinct now available for that purpose is of interest in this connection' i-Seriate X X X X 2-Seriate S-Sekiate 4-.SEKIATE A. Bidwillii "... X X X X X X 1 X — . — wurtembergianum Schmidianum . . . hugelianum excelsa i . . arizonicum . . . Edvardianum . . . virginianum Doeringii . . subtile . . argilliacola .... Heerii .... Cunninghamii' '.obertianum . . i X * Kxistii ig species. II 63 ANATOMY OF THE GYMNOSPERMS Such a comparison brings into strong relief the fact that the Araucarias, both past and present, constitute a transitional group with a somewhat wide range of variations, and in this respect they may be said to stand between the more stable Cordaites and Dammara on the one hand, and the far more variable Coni- ferae on the other, since in Dammara australis we find essentially the same features of structure and distribution as in Cordaites, the pits being one- to three-seriate. The sequence presented above may be held to be in the inverse order of development, and A. Robertianum must therefore be held to represent the most primitive form. It is apparent that in Cordaites, Araucaria (including Arauca- rioxylon), and Dammara the pits are invariably distinguished by two constant features, — ( i ) their hexagonal form, and (2) their very compact disposition throughout the entire extent of the tracheid. They often deviate from the multi-^eriate arrangement typical of the group as a whole in that in individual cases they are reduced to a one-seriate arrangement. They thus tend to overlap the next group, which is distinguished by a two-seriate disposition, but any confusion which might arise from this cause may be overcome by reference to the special form and disposi- tion of the pits, as will more fully appear in the following lines. Among the remaining Coniferales twenty species of various genera, or 17.2 per cent in all, show a two-seriate arrangement, and to this group we must also add the Gingkoales and various fossil species. Here the multiseriate disposition of the pits involves features which at once distinguish the group as a whole from the preceding, clearly placing it upon a higher plane of development. The pits are never hexagonal but are generally elliptical or round, while they also show a strong tendency to extreme segregation. When brought into a compact arrangement, as in Cupressoxylon, Sequoia, or various species of Pinus, they are flattened only along the lines of limited contact, which are usually confined to one end of the pit (fig. 8). A very characteristic feature of this group is the further fact that the two-seriate arrangement is not constant, either in tl 0 same section or in the same tracheid. Both Pinus BURUERtU FI'IS 63 taeda and P. cubeniis, as also Larix americana and ''suga cana- densis, afford illustrations that, while typically two-seriate, a given section may show a strictly one-seriate arrangement, and this difference also obtains as between contiguous cells. In all such cases examination will show that the variation is directly related to the relative size of the tracheids in such a way that the narrower tracheids, or those arising from a less vigorous growth, are one-seriate. Within the individual trachcid thert; is (SB ^ CD FiG.g. PiNUS STROBUS. Kadial section showing the form and disposition of the bordered pit.s. x 280 F10.8. PiNus CUBENSIS. Radial section showing the form and disposition of the bordered pits. X 280 a strong tendency to a one-seriate arrangement in the central region, while it is two-seriate at the extremities ; and this law holds so true that in those species which are exceptionally two- seriate judgment should be reserved until it is seen that the one-seriate form holds throughout. The antithesis of the multiseriate type is found in the one- .scriate form. This is typical of 50 per cent of all the species included in the present studies. In such cases the form of the pit is never hexagonal or specially flattened. When the disposi- tion is somewhat compact, as in Pinus strobus (fig. 9), the outline ii ■ p¥ = 44 ANATOMY OF THE GYMNOSPERMS becomes more or less strongly elliptical, but as the segregation- is more pronounced a definitely circular form prevails (fig. 10). Within the limits of the individual trucheid the same law of dis- tribution obt« IS as in the two-seriate type, whereby segregation is always most pronounced in the central region. Between species of the strictly one-seriate and those of the strictly two-scriate type there is an intermediate or transition group comprising thirty-four species, or 29.3 per cent of the in vestigated species, into which members of the other two groups may occasionally be projected. The distin- guishing feature of this group is the occur- rence of pits in pairs, which are usually distant and in no case so numerous as to distinguish a two-seriate disposition. They give undoubted proof of the passage from one type to the other. Like the two-seriate type, this feature is not confined to any one genus or to any particular group of genera, but it applies with equal force to any genus, the members of which may therefore represent any or all of the three types here specified. Viewing the distribution of the bordered ^'bu's° Radia?seJr„ P'^' from the Standpoint of zonal devel- showing the bordered opmcnt, it is found to be Universally true strongest tendency to a mult '"seriate arrange- ment. With a radial increase of the xylem this tendency con- stantly diminishes, with the general result that the pits becoi..o more strictly one-seriate and more distant toward the summer wood in which they are sometimes wholly obliterated, this being the case when the cell wall acquires unusual thickness. Upon careful examination the foregoing facts will be found to be in exact accord with the law formulated by De Bary with reference to variations in the structure of spiral tracheids and the genesis of bordered pits, as already stated. In accordance with this law it is possible to conclude that relatively rapid BORDERED PITS t»s growth IS coordinated with a primitive development, while he converse is true of a slow rate of growth which i^ again con- vertible into terms of maturity. On th« basis we may pr. sent the following general outline of sequence in development, as prehmmary to further and more dctailcti discusHion of phylogeny : a-S Mriate, hexagonal pits 1-4 seriate, hetagunal pit* '-3 •"■iate, hexagonal pits 1-3 seriate, hexagonal pim '-2 seriate, round or oval pits Higher Coniferales, 1-2 seriate, round or oval pits Higher Coniferales, i-seriate and pairs, round or oval pits Higher Coniferales, i-seriate, round or oval pits Cordaitcs . . Araucarinxylon Araucaria Dammara. . Giagko Compai^ throughi ui ii,r irai lieid. Mi>re or 1 (■■.«, ■ often stronjif!, , segrcirated. Tangential walls. The occurrence of bordered / ', in the tangential walls is a well-known and characteristic feature f the Conifers:. In the case of fossil forms, to which Araucai- oxylon offers a partial exception, they cannot be satisfact(,rilv demonstrated because of the peculiar altera- tions of the cell wall, but that they are pres- ent we are permitted to in* r from analogy with existing species upon which dependence must be placed for an eluv idation of the gen- eral law. The typical posit i< a for such pits is upon the tangential walls of the summer wood, where they arc seen most satisfactorily in radial section, inasmuch as they are always , . ..^ readily observable when present, and their v^,•..^^7^^^ ,,, most essential features are displayed in a gantea. Radial sec manner not possible in a tangential section *'°" ^howinij bordered (fia ii\ pits in the tangential ^ *■ , '■ walls of the summer This position obviously results because of **"°^- ^ ^^ limitation of the radial walls throi-h radial compression. The pits are therefore always confine! to the few outermost tracheids of the last-formed summer wood, -nd .n some cases they are con- fined exclusively to the last tracheifi. fe-t p m i ■ ' i 66 ANATOMY OF THE GYMNOSPERMS Pits occur in this position in '/ij per cent of all the investi- gated species, and their absence in 28.3 per cent points to some special features in development which may be assumed to have a general bearing upon the questions of descent and relationship. In Dammara, as represented by the one species D. australis, such pits are a prominent and characteristic feature, but in the nearly related Araucaria they are remarkable for their uniform absence. In the primitive Gingkoales they are also present, but among the Taxaceas, while generally present, they are occasionally wanting, as in Torreya taxifolia and T. nucifera, or in 06.6 per cent of the investigated species of that genus. Nowhere else among the Coniferales do we find such a leature until we reach the genus Pinus, the second and higher section of which is almost invariably characterized by their absence, thus presenting an exceptional feature to the extent of 68.3 per cent of that genus. That such absence represents a process of obliteration conformable to De Bary's law cannot be doubted, while the sporadic recurrence of this feature in often widely separated genera, or in particular spe- cies of a given genus, must be held to have a more or less direct bearing upon the general course of development. This is empha- sized by the observation that in Larix americana and L. lepto- lepis, as also in Picea bicolor, there is a more or less pronounced tendency to an obliteration which is never fully developed. This is expressed in the somewhat remote position of the pits and their very small size, which renders them obscure and often diffi- cult to discover. In this respect these species represent transi- tional forms. As an exceptional feature bordered pits may sometimes be found upon the tangential walls of the spring wood. This is espe- cially noticeable at the ends, of tracheids, and in rare cases it may apply to the entire extent of the wall. The most notable instance of this kind, because practically unique, is to be met with in Sequoia gigantca (figs. 1 2 and 1 3). Those spring tracheids which lie in direct contact with the summer wood of the pre- vious year often exhibit this feature with great prominence, but it may also extend radially through several successive tracheids. BORDERED PITS 67 © © This IS undoubtedly a primitive character, and in the one case cited It possesses some value for the purpose of specific differ- entiation, but in general terms the occurrence of bordered pits in such positions is of so sporadic a nature as to give this feature no well-defined value, either for taxonomic or phylogenetic purposes! It may, nevertheless, be stated with respect to the pits on the tangential walls of the tra- cheids in general, that in their distribution they distinctly conform to the law governing simi'.'r structures on the radial walls. Reference to Cordaites acadianum shows that in the multiseriate pits of the hexagonal form these structures always preserve the spiral arrange- ment character- ist ic of the structures from which they fig. 12. sequou gi- were derived "antfa. Radial (plates 3-6), and this con- formity also ex- tends to the direction of the spirals which gen- erally ascend from left to right. The general law in this respect has already been formulated so fully Fi<;. 13. Sequoia gioantea. Tan- ''^ ^^ ^^^V (^^' '^3) as to make it gentiai section showing bordered unnecessary at this time to enter pits in the taneential walls of thp _ -a. . . spring wood. «^ 4'^' "'"'* "f 'he upon ,ts Consideration more in detail, beyond a reference to one or two special features and some apparently exceptional ca.ses. U hi e the spiral arrangement is always typical in such genera as Cordaites, Danimara, Araucaria, etc., it is not obvious in those cases where the pits are strictly ore-seriate and often remote section showing the bordered pits on the tangential walls , of the .spring wood. X 280 © 68 ANATOMY OF THE GYMNOSPERMS i M from one another. Nor is it apparent at first sight in those cases of two-seriate pits where, as in Cupressoxylon Dawsoni from the Cretaceous, Larix americana. Sequoia, and various species of Pinus, the pits are always paired off in such a way that the axis of each pair is at right angles to the axis of the cell (fig. 8). Two explanations are here possible : (i) the spirals are in reality two-seriate, and are projected through the alternate members of the two rows of pits ; or (2) the disposition of the pits repre- I sents an extreme phase in the flattening of the original spirals conformably to a higher type of development. This view, which seems the more reasonable, is in direct harmony with De Bary's law, while it receives additional support from the form and direction of the pit orifice. The orifice of the pit is variable, at differ- ent times being round, when the pits are also round and more or less distant ; oval or oblong, when the pits assume corresponding forms; or, in the summer wood, lenticular or oblong. The transversely elliptical pits of Pinus stro- bus (fig. 9), the orifice of which is also trans- versely oblong, as also the similar pits of Pinus ""gens. Torde'rTd ''"''^"''^ ^^^^ ^^' ^^^''^ Substantial proof in pits on the radial Confirmation of the probable correctness of walls of the sum- this view. In the summer wood the pit orifice mer wood, x 280 , ... commonly assumes a position which appears to offer a direct contradiction to this conclusion. In Pinus strobus (fig. 10) the orifice is oblong and parallel with the tracheid axis. In Pinus pungens, as in many others of the same genus (fig. 14), the narrow orifice is extended above and below into a diagonal slit of great length, forming a narrow angle with the tracheid axis. At first sight this would seem to imply that these features represent primitive spirals, the original direction of which has not been greatly if at all modified, but one or two considerations will assist us to a correct interpretation of this feature. In the BORDERED PITS 69 I (2 m Fig. 15. CupREssus noot- KATENsis. Radial section showing deformed bor- dered pits. X 280 o first place, it is to be observed that such positions and modifications of the orifice are invariably associated with the summer wood; if they occur in the spring wood, it is the result of maceration and commonly appears in fossil plants or woods in process of decay, and they are always moi,t conspicuous in those tracheids which have experienced the most profound modifications with respect to the growth in thickness of the secondary walls. It has already been shown in the case of Taxus and Torreya that there is no necessary connection between the spiral bands and the spiral lines of striation, — that, as a matter of fact, as particularly illustrated by Torreya taxifolia, the two arc quite distinct from one another under ordi- nary conditions of development ; but in cases where the wall experiences extreme growth in thickn-^ss the obliteration of the original spiral structure is complete, and at the same time it is replaced by the normal striation of the wall, which then becomes most pronounced. Instances .such as those afforded by Pinus strobus and P. insignis may, according to this in- terpretation, be held to represent the final phases in the obliteration of the original spirals, and they therefore constitute char- acters indicative of the highest type of de- velopment. In a few cases the structure of the bordered pit presents exceptional forms. In Cupressus nootkatensis the pit orifice shows either unusual want of regu- larity in outline and marked eccentricity of position, or it is so enlarged as to leave only a narrow border to the round or oval pit (fig. 15). Similar features occur occasionally in other genera, and they are generally conspicuous in Pinus tieda. De Bary has directed attention to the same feature in Ephedra (13, 159) and Pinus sylvestris, and he correctly interprets it as a form of arrested development. Alterations also arise as a feature of 70 ANATOMY OF THE GYMNOSPERMS <0) secondary growth in those cases in which the wall acquires unusual thickness. This is typically the case in Pinus cubensis where m plan (fig. i6) the orifice is extended vertically to a length often twice the diameter of the original pit. In tangential section, according to the particular direction of the plane of section (fig. 17), the orifice is either of uni- form width or it enlarges BENsis. Radial Constantly through the en- H7"°J!i,l*'?'"5 *'■■« thickness of tho later deformed bordered pits. X280 growth, from within out- wards. That such unusual forms are features of extreme secondary growth of the wall, and that they may be anticipated in all cases where such modi- fications of the walls occur, is a reasonable deduction from the observed facts. (!) Fig. 16. Pinus cu- Fig. 17. Pinus CUBEN- SIS. Tangential sec- tion of bordered pits as in fig. 16. X 280 Bordered Pits — Taxonomic and Phvlogenetic For taxonomic purposes the bordered pits possess a definite though often limited value. In the genus Cordaites, as also in Araucarioxylon, Araucaria, and Dammara, this is expressed in the hexagonal form together with their very compact, chiefly multisenate arrangement throughout the entire extent of the tracheids,— characters which are of generic value and at once serve to separate these genera from all others. The contrast- ing differential feature is then to be found in the pits of the oval or round form, together with their two-seriate or one-seriate dis- position, with a more or less marked tendency to segregation rhis IS characteristic of the Gingkoales and all the Coniferales, both fossil and recent. As a differential character of subgeneric value, the occurrence of bordered pits on the tangential walls of the summer wood of BORDERED PUS 71 the firs section of Pinus (the soft pines) and their almost mvarmbe absence from the same structural region in the second section the hard pmes) is one which may be always relied upon For the purposes of specific dif?crentiations the pits onVhe tangential walls possess a distinctly inferior value, which must be confirmed m most cases by the evidence of other factors Their utility m this respect is made sufficiently clear in the various cliagnoses and m the artificial key. without further discussion at this time. In the genus Cordaites, according to the provisional specific differentiations of fossil forms as at present generally empl^ed. the number of rows of pits, or their segregation into definite groups, are characters of well-defined specific value, since they are among the few features which maybe utilized with certainty for this purpose. Thus C. acadianum with its two to five rows C. matenanum with two. rarely three to four, rows, C. hamiU tonense with two rows, and C. Newberryi with two rows, in groups o SIX to thirteen pits, rest upon a basis which is not only easy of recognition but which may be applied with full assurance In Araucaria the three species investigated may be similarly differentiated from one another. The same rule is applicable to Torreya taxifolia. which is thereby separable from the other spe- cies; likewise to Cupressoxylon Dawsoni. Tsuga canadensis, aVd Larix amencana. and. among the pines, to P. Lambertiana, P. clausa, P. Sabmiana, P. ta^da, P. palustris. and P. cubensis. It IS to be observed, however, that the constancy which charac- terizes this feature in Cordaites and Araucaria is wanting in the higher Abietinea.. In Larix there is such variation that very careful scrutmy is required, while in the genus Pinus the num ber of exceptions to the typical character increases greatly and is liable to cause some difficulty in the final determinations unless much care ,s exercised. Pinus treda offers a conspicuous illustra- lon of this fact, as may be seen by reference to the analytical key. It IS therefore manifest that the value of the bordered pit tor taxonomic purposes is most clearly defined in the lower types of the Coniferales. and that their value diminishes steadily with 72 ANATOMY OF THE GYMNOSPERMS an advance towards higher forms of organization and develop- ment. In all cases where exceptional forms introduce diagnostic difficulties these may be overcome by the controlling effect of associated characters. We are now in a position to examine the data at hand with a view to determining the bearing of the bordered pits upon ques- tions of phylogeny. Having reference to the origin of the bordered pit and the various modifications it presents in the course of development, it cannot be doubted that the hexagonal, multiseriate pits of Cordaites, Araucarioxylon, Araucaria, and Dammara place these genera in a relatively inferior position, — a view which gains a large measure of support from the well-known and extensively multiseriate disposition shown in Heterangium Grievii (81, 341), but the facts so far discussed have not as yet thrown any special light upon the relative positions of the separate genera. An examination of twelve species of Cordaites shows that the bordered pits exhibit a much wider range of serial variation than any other genus covered by the present studies. If then we accept the general principle with respect to the development of the bordered pits as already illustrated, it cannot be doubted that the two- to five-seriate pits stand much nearer to the primitive form of the tracheid than do the one-seriate. From this point of view it is then evident that in C. recentium, the name of which is thereby seen to be fully justified, the one-seriate pits place it at the upper end of a series which has its inferior termination in the two- to five-seriate C. acadianum, while intermediate forms appear between the two as members of a series of nine variants, and it is possible to arrange these in such a manner as to exhibit the probable sequence in development, as seen by table on the following page. The wide range of variations here shown, especially when compared with other genera, ..t once serves to suggest that Cordaites was in this respect somewhat of the nature of a tran- sition group from which others were given off, or else that it epitomized the collective changes through which a number of BORDERED PITS 73 genera must have passed. And inasmuch as this genus ex hib.ts a more highly developed multiseriate arrangement than any other within the general phylum, we must concede that it IS, with respect to this character, the most primitive of all. Serial Variations in the Borderei. Fits ok Corimites C. acadianum ohioense . . . ouangondianum materiarium Clarkei . annulatum Brandlingii materioide illinoLsense hamiltoneiiMe Newberryi recentium The genus Araucaria shows a much more restricted range of variations, there being only four variants pretty uniformly dis- tributed among fourteen species, both recent and fossil (a^tc p. 6 1). While the most highly developed members, four in num' l)er are represented by one-seriate pits, the most primitive form of four-senate pits occurs in only one case, -A. Robertianum It ,s therefore manifest that this genus is obviously of a more n.lvanced type than Cordaites, from which it undoubtedly origi- nated. Dammara being represented by only one s,>ecies, it ^s not possible to locate it more definitely than to say that the one- to three-seriate disposition of its pits would place it in a posi- tion equivalent to that occupied by Araucaria Cunninghamii, and therefore about three fourths of the way down the scale for that senus. This fact points with much force to the idea that of the two genera Dammara is of relatively lower type. H 74 ANATOMY OF THE C.YMNOSPERMS The Gingkoalcs and the Conifcralcs as a whole exhibit an obviously higher tyj)e of development than the preceding group, in consequence of the more pronounced tendency to segrega- tion of the pits, which are now either elliptical or round, and never hexagonal. This distinction is so clearly defined and con- stant as to support the idea, which gains force in other ways, that Cordaites, Araucaria, and Dammara are clearly related members of a principal branch of the original stock, and that they therefore diverge considerably from the particular line of descent within which we find both the Gingkoales and the Coniferales. Gingko, being the unique representative of an ancient line, cannot very well be brought into the present discussion very much in detail. On other grounds it is known to be a primitive form representing a group distinctly inferior to the Coniferales, and this view is supported by the disposition of the pits in two series, a character which, if taken alone, weald give the genus rank with Torreya taxifolia among the Taxaceae, but when re- garded collectively would phce the genus distinctly below the Co- niferales as a whole. This evidence, then, indicates that the Gingkoales must have arisen as a side line at some point inferior to the Coniferales but superior to the Cordaitales. In the Taxacert the bordered pits do not in themselves afford very conclusive evidence as to the relative position of the family. Among the eight investigated species, representative of three genera, only three, and chiefly two, variants occur. Taken alone, the disposition of the pits would lead to no final conclusion, but other factors permit of placing this family in the inferior posi- tion usually assigned to it. In the genu.s three variants are found, — the one-to-two rows of T. ta\if(»]ia, the one row or pairs of T. californica, and tic strictly <>!.■ seriate form of T. nucifera. In Taxus only two variants apj). ar, — the one row or pairs of T floridana and the one-soriate disposition as found in the remaining three species. The one representative of Podo- carpus shows but one variant, and that is one-seriate. From this it is obvious that tho generic sequence must be in the order BORDEREP PITS 75 given, and that the sequence of species must be approximatclv as g,vcn in the table of anatomical cbta ' PP^^^'niatcIy The observations so far made apply altogether to the pits on he radial walls. We may now pass to a considen^tion If their relation to the tangential walls, a factor which does not call for very extended discussion. This feature is found to apply to 71.7 per cent of all investigated species exclusive of fossils It .8 wantmg m three species of Araucaria. representing 2 58 per cent ; m two species of Torreya. or , .72 per cent ; andin the entire second section of Pi„us to the extent of twenty-eight speces. or 24.. per cent. But the occurrence of pits on fhe tangentul walls, in common with those on the radial walls i! a we l-known feature of the Sigillarias («i. .98). where he pnm.nve character is well established, and we cTn hardly doub that the.r final el.mmation in the higher pines is the expres- s.on of a final phase in development consistent with the pos tion usually assigned those plants. I^sinon The absence of pits from the tangential walls of certain tZTT 7 "^""^'^ " ^° ^ '"^^^P-^^d - -« of those I.Td '""''■' ' '''''''' 'yP' °^ development which never become permanent in the same line, but which are to be met with as one of the invariable features of evolution The remaming genera of the Conlferales present so few devia- Xon^tl^*^"'''! '^'V"'' '^'y ^^""°^ ^' differentiated ful y on the basis of the bordered pits. This character never- theless has a definite value in association with others, as in the genus Sequoia or some of the hard pines. Larix americana. etc he general sequence of genera may be recognized by the bor- le.ed p.s only m so far as these structures serve to confirm and emphasize the conclusions reached in other ways, and this elr 'hT' T^^'T ^'■°'" '" '"''P^^^'^" °^ '^' ^-ble already referred to. It will nevertheless serve a useful purpose at the present moment to ascertain the general sequence based upon h ;:;7'^"^^f „d'«t"bution of the principal variants, as seen by the table on following page. ' Appendix A. 'Ill 76 ANATOMY OF THE ClYMNOSPERMS Comparison op the PRiNriPAi. Variations in tiii Serial Arranok- MEN! -ir Bordered Pits, hv Pkrckntaoks TllTAl " — — . 1 Vakiatiuhi 'i J-4 *-j 'J 3 1-1 Paim 1 Cordaites . . 9 «3 JSO i6.6 25* ■6.6 33-3 Uammara . . 1 6.6 20.0 400 Araucana . . f'ingko . . . 4 6.6 20.0 40.0 lOO.C J3-3 Sequoia . . 1 1 lOO.O Larix . . . 3 2 I Taxodium . . 3J3 33 3 333 Libocedrus 25.0 100.0 75.0 Thuya . . . I 100.0 Pseudotfuga . Pinus . . . 3 3 3 2 50.0 50.0 Abiet . . . 17.1 4' 5 41-4 Taxui . . . 136 *7-3 59.1 Tsuga . . . Picea . . . 3 2 16.7 25.0 16.7 75-0 66.6 Podocarpus 1 10.0 90.0 1 .,^»» Thujopsia . , Cryptomeria . I 1 100.0 100.0 With respect to specific differentiations it has already ap- peared that the bordered pits may be employed with success in Taxus and Torreya. In Cupressus this rule also applies to C. pisifera and C. macrocarpa, both of which are distinguished by having their pits in one row or pairs, while the remaining seven species have strictly one-seriate pits. An instructive ex- ample is afforded by Cupressoxylon Dawsoni. In this species, which is of early T'^rtiary age (Lignite Tertiary), the pits are typically two-seriate, being disposed in a very compact manner similar to that found in existing Sequoias. But in a series of eleven specimens it is clearly seen that two variants are repre- sented, the second being a one-seriate form. These variations are also found, as in the other Coniferales, to be directly related to variations in the size and rate of growth of the tracheid. It cannot be doubted, then, that C. Dawsoni is a more primitive BORDERED PITS 77 reprcientative than any species now existing, and that it is sub- .tant.,.y the ancestral form of the genus, so far as we know In I^ru the four investigated species may be differentiated pretty fully, and this rule applies w^th particular force ^f amrncana and L. occidentalis. both of which are distinguished' by t w<>-senate forms. Among the pines P. Lambertiana, P clau« '. Sabm..^ P. t«da. P. palustris. and P cubensis arc reaS"; d ffercntuted from the others by the two-seriate pits. In U other cases than those specifically indicated the bordered pits afford an madeqimte basis for specific differentiation. ^ It >s now apparent that segregated round or oval pits in one ZtTn th r ", ^'/'^P'^-"^-^ '^^ highest type o'f develop ment m the Comferales. and any deviation from this must L taken to mdicate the survival of more primitive conditions. po,n mg to derivation from a type like that of Araucarilo Corcaucs. Prom this point of view the occurrence of pits in oncto-two rows in Larix americana. Torreya taxifolia. Sequoia. Tsuga canadensis, and various species of Pinus indicates the survival of ancestral characters which are partial to the extent of 7.2 per cent, and complete to the extent of 10.8 per cent That such deviations from the usual type of structure are either survivals or reversions which serve to indicate a common origin cannot be doubted, more especially as they do not occur at a fixed point near the original type, but they arise sporadically n widely separated genera. The tendency of such evidence, hen IS to show a common ancestry for the various genera of the Taxaceae and Conifers, a view which is greatly strength- ened by the testimony afforded by the spiral tracheids of Larix americana. Pseudotsuga. and Pinus tada. MHCROCOrV RBOIUTION TiST CHART (ANSI and ISO TEST CHART No. 2) 1.0 1.1 Li 123 |23 ■ 2.0 kbu U£ lu III ^-^ lll^^s ^ /APPLIED IIVHGE Inc ^^- 1653 East Main Street r-S Roctiester. New York 1*609 USA Jgg (716) 482 - 0300 - Phone ass (716) 2SS - 5989 - Fax Ij CHAPTER V MEDULLARY RAYS General Structure The medullary ray, in the various details of its structure, as presented radially and tangentially, comprises some of the most important features for diagnostic and taxonomic pur- poses. While it presents numerous variations, these are, in the main, of such a nature as to give them very positive value for both generic and specific differentiations. Primarily the medul- lary rays are to be regarded as a residue of the original funda- mental structure, which has been left over in the genesis of the primary stele, but they are capable of reproduction or extension under the influence of the cambium in the course of secondary growth. In all such cases, however, they are typically composed of the same elements which are necessarily parenchymatous. Deviations from this structure may appear through the intro- duction of other elements, but such alterations always arise in a manner which indicates their relation to the evolution of higher types of organization. In a transverse section the medullary ray appears usually as a si"iple, radial series of elongated cells with transverse termi- nations. Deviations from this type of structure occur only in the case of the rather rare two-seriate forms, which appear in the transverse plane of section only at wide intervals, or in the case of rays which contain resin passages, as in Picea, Pinus, Larix, etc., when the structure presents a varying aspect depend- ent upon the particular plane of section. In Pinus reflexa the side walls of the ray cells may be seen projecting into the cavities of adjacent tracheids, where they form short, saclike bodies of the general nature of thyloses, which they really 78 MEDULLARY RAYS yg are (fig. i8). Such a feature is of specific value in differentia- tion. With this exception the ray presents no features in this plane of section which merit special consideration Radia/ section. Viewed radially, the medullary ray is seen to be composed of a series of cells e.xtended in a radial direction and superimposed so as to form a muriform band from one to many cells in height. In general terms, the higher the ray the lower the component elements, from which it follows that in one-celled rays the cells are usually highest ; but this feature is only of general interest, since it rarely has a bearing upon the chief ques- tions at issue. In some cases two struc- tural types may be recognized, — the one containing resin passages, the other devoid of such structures. Where such passages occur the structure of the ray shows a variation of detail which makes it of no value for diagnostic purposes, and the rela- tion is one which possesses interest only in so far as it applie,- to the distribution of the resin passages themselves. A feature of primary importance in the constitution of the ray is the occurrence of two kinds of parenchyma cells. In 95 Fig. 18. p.nus keklexa. per cent of the genera the upper and lower Transverse .section of walls are always thickened by secondary ^ '"'''"""^ "^ '^°" growth and more or less strongly perfo- rated by simple pits (figs. 19 d, 25, and 2;). This feature also applies to 56.1 per cent of the genus Pinus It possesses no special value for either sj^ecific or generic differ- entiations except so far as it .^plies to cells which are markedly different and justify the special terms fhcl- walkcUnA thin zvalled. It is obvious, then, that the thick-walled cell is to be regarded as the normal structure for the ray of the Coniferales as a whole, while the thin-walled represents the exceptional form which is introduced in response to some special demands. Although the ing the inflation of the cells opposite tracheid.s. X 300 8o ANATOMY OF THE GYMNOSPERMS thick-walled cells occur in the genus Pinus to the extent of 56 per cent, they show a diminishing frequency, eventually becoming rare and are ultimately replaced by thin-walled cells. Reference to them in the following diagnoses is always specified by ( i). In 43.9 per cent of the genus the upper and lower walls are thin and absolutely devoid of pits. For diagnostic purposes such cells are always referred to as (2). In some cases they are so undeveloped as to be obscure and readily broken out in the process of section Fig. 19. Pinus palustris. Radial section of a medullary ray showing charac- teristic pits on the lateral walls : a, a thin wall broken out ; b, thick-walled parenchyma; <-, thin-walled parenchyma, x 280 cutting, so that they are often entirely wanting (fig. 19, a-<). Such thin-walled cells are typically developed m P. palustris, P. taeda, etc., and it is to be observed that they are always asso- ciated with the highest forms of development. Transition forms occur. These are first seen in the soft pines, where occasional thin-walled cells devoid of pits are interspersed and are often conterminous with the thick-walled elements. In the ha*- dnes the same relation e.\ists, but it is gradually reversed u. a the MEDULLARY RAYS 8i thin-walled cells altogether predominate. Such gradations are exhibited in P. Coulteri, P. Jeffreyi, P. pungens, P. tieda. P cu- bensis. and P. inops, and they afford valuable evidence as to the sequence in development of the species. In P Murrayana P. cubensis. and P. insignis the transition forms e.xhibit much more detailed gradations, by virtue of which it is often ex ceedmgly difficult to Jistinguish between the two forms of cell since whether conterminous or parallel the variations in thickness "^""tion IfTflT "'^j-CHUM. Medullary ray showing the structure and posi- t on of the p ts on the lateral walls; the straight ray cells and the thin straight, terminal walls, x 280 ^ j- i.c.is ana ine tnin, change in such a way that the one type passes gradually into the other. When these variations are viewed collectively and taken together with the general fact that the thin-walled cells are a feature of the higher types of organization, we may reason- ably conclude that the thin-walled cells have been derived from the thick-walled through a process of arrested development. The cause of such alterations is to be sought for, and it will doubt- less be found in connection with another component of the ray. The terminal walls of the ray cells present three typical vari- ai.ons, — (,) thin-walled and entire, (2) thin-walled and locally thickened, and (3) thick-walled and coarsely pitted.^ The first ' See Appendix A. 8a ANAIOMY OF THE (lYMNOSPKRMS feature is a characteristic of 5 2.6 per cent of all the genera, inclu- sive of Gingko, from Dammara to Sequoia, while it also appears in Cupressus and Abies in part as exceptional, and in the genus Pinus to the extent of 85.3 per cent. The wall presents no secondary growth in thickness, either locally or generally. In the majority of cases it crosses the line of the principal cell axis either at right angles or diagonally, — features which are usually of very second- ary value, although in a fe^' ca^es, as Taxodium, it may serve a useful purpose as an associated character for differentiation from closely allied genera (fig. 20). In other cases the wall is more or less strongly curved. This feature is prominent in Thuya, Cupressus, Podo- carpus, Thujopsis, and Cryptomeria, as also in the more highly devel- oped hard pines. To a less extent it also oc- curs in Ta.\odium, and it constitutes a char- acter of some value for differential purposes (fig. 21). The second variant differs from the first in that the otherwise thin wall is locally thickened (fig. 22), the secondary growth forming one or more beaded enlargements. This is a feature which occuis exceptionally in Abies, Pseudotsuga, Picea, and Pinus, but it is typical in Cupressus (66 per cent) and Juniperus (72.7 per cent), where it constitutes a diagnostic element of great value. It is in all cases, however, to be regarded as a transi- tional form between the first and the third variant, and from this point of view it also possesses a somewhat definite phylogenetic value. The third variant is characterized by a marked general, secondary growth of the wall, which thereby becomes more or less strongly thickened and traversed by numerous simple pits Fu;. 21. Thuya GIGANTEA. Medullary ray show- ing the form and disposition of the pits on the lateral walls ; the thin and curved terminal walls ; the cells contracted • the ends, x 280 MKI)L'J,I..\kV RAYS 83 (fig. 23). It occurs exceptionally in Juniperus and Pinus. but it IS typical m Abies (90.9 per cent). Tsuga (100 per cent), Larix (100 per cent), and Kcea (90 per cent). In Abies and Juniperus. where transitional forms sometimes occur, the walls in the spring Fig 22^ CUPRESSUS Macnabiana. Medullary ray showing the form and position of the pits; the thin, curved, and locally thickened terminal walls, x 280 wood may be only locally thickened, but in such cases the typ- ical feature always appears in the summer wood, where such secondary alterations are most strongly emphasized. For taxonomic purposes such features possess a definite value. The thick-walled cells of Tsuga. Larix, and Picea p rmit of an Fig. 23. Juniperus occidentaliS. Medullary ray showing the form and dispo sition of the pits on the lateral walls ; the thick and coarsely pitted termin .1 walls. X 280 easy and definite segregation of these three genera in those cases which otherwise might involve a strong element of doubt, and the same rule holds true, though to a less extent, with respect to the locally thickened walls in Cupressus and related genera. Pits on the lateral walls of the ray cells are an invariable feature of all investigated species of Gingkoales and Coniferales, 84 AN'ATO' V OF THE (lYMNOSl'ERMS including fossil reprc^atatives and the Cordaitales. They vary very much in form, size, and number. In such types as Junip- erus they are most diminutive (fig. 23) and generally numerous, while in many of the pines, such as P. resinosa or P. koraiensis Fig. 24. PiNUS refi.exa. Medullary ray showing („) the form and disposition of the pits on the lateral walls ; {/>) the ray tracheids. x 280 or p. reflexa (fig. 24), they attain to maximum 3ize and occupy nearly the entire surface of the wall within the limits of a wood tracheid, thereby becoming few in number. In Sequoia (fig. 25) or Taxodium (fig. 20) they are typically oval, in Pinus cubensis Fig. 25. Sequoia gigantea. Medullary ray showing the form and disposition of the pits or. the lateral walls, x 280 or P. taeda (fig. 26) they are variously lenticular, while in P. resi- nosa or P. koraiensis they are oval or oblong, or even quad- rangular. Such variations as a whole are far more numerous and sharply defined in Pinus than in any other genus known. In all the investigated genera the pit is bordered. This finds MKUUU^RV kA\ S5 either partuil or complete exceptions in the geni-.s Piniis to the extent of 78.1 percent of the spjcies, in which the pits are either simple throughout or else they exhibit a more ..r less definite bor- der in the summer wood only. That a border is a characteristic feature of fossil representatives is justified by comparison with existing species, but it is not always recognizable in consequence of the alterations of structure due to the general process of petrifaction. Such obliteration not infrequently involves the pit orifice also. It is thus apparent that such structures often fail m the determination of fossils. In existing species the border dentat... walls; (2) the structure of the parenchyma cells; (3) tracheids con- t' -mir.ous with parenchyma cells, x 280 n so faintly defined as to be difficult of recognition, and especially the case in rays of a resinous character. In such cases, however, the requirements of a correct diagnosis are fully met by the pit orifice. The general law of development, then, is such that all genera except Pinus may be held to be characterized by bordered pits. Their strong tendency to obliter- ation in that genus is found to coincide with the more marked development of ray tracheids, which undoubtedly assume more completely the original functions of the parenchyma cells, these latter in consequence suffering constant structural reduction, as in the hard pines. "f 86 ANATOMY OF THE (lYMNOSPERMS In the distribution of the pits an important feature appears in the numerical variation in different parts of the ray. Foi diag- nostic purposes it is necessary to have reference to the number of pits not upon the entire surface of an individual cell but within the limits of a spring or summer tracheid, as the case may be. They are invariably most numerous in the region of the earliest spring tracheids, usually diminishing toward the summer wood, where the change may sometimes take place ab- ruptly, and in which they are most commonly reduced to one, with occasional obliteration in the most highly modified tracheids last formed. A similar law of distribution is applicable within the vertical limits of the ray. When these structures are several cells in height the number of pits is typical, and, within certain narrow limits, constant for all except the marginal cells. Thus if the normal number is one to two for the central cells, it may sometimes rise to four, si.x, or eight in the marginal cells only, and such exceptions must be noted in diagnosis. When the ray is only one cell in height the number of pits agrees with that for the marginal cells. Such numerical variations possess but little value for generic purposes, but as a specific character they may be held to constitute the principal differential feature in the last analysis. These relations are expressed typically in the genus Sequoia, the two species of which may be definitely differentiated. S. gigantea is characterized by oval and com- monly narrowly bordered pits, the broadly oblong orifice eo-nl to the outer limits of the pit and chiefly parallel with the cell . ^is, one to two, more rarely three to four, per tracheid. In some- what sharp and definite contrast to this, S. sempervirens has large, oval, narrowly bordered pits, two to six jjer tracheid, the round or broadly oblong orifice being cither parallel with or diag- onal to the cell axis. In Libocedrus the pits are small, narrowly bordered, oval, with a lenticular, diagonal orifice, one to four per tracheid. Or again, in Larix americana, the pits are " two to six per tracheid, becoming distinctly smaller toward the summer wood where they are abruptly reduced to two and finally one per tracheid." In Cupressus pisifera the pits are "chiefly two Mi:nui.i.Akv ravs B7 in radial series, „r in fho niarKinal colls and low rays upwards ..f ..X ,K-r trachcid,- In Tax.Klium distichum the pits are round, conapicuously bordered, and br^e. with a very narrowly lenticu- lar and d>.„-onal orifice, which is often as long as the outer limits of the pit. But in the analytical key it will be observed that this genus is naturally brought into close relations with Sequoia which IS also distingu ,hed by large bordered pits. The ulti' mate differentiation then rests upon the fact that in the latter the pits are 07'a/, the border often narrcw, sometimes odscun; while the 03/o»^ or lenticular, usually rather broad, orifice is generally parallel with the cell axis. As a final illustration, the four pits of Pinus monophylla, or the one t<. five throughout, finally reduced to one to two in the summer wood of V Bal- fouriana, point with much definiteness to these particular si>ecies while among the hard pines the occurrence of large oval or squarish pits, one or rarely two per tracheid, segregates a group of four species. Detailed as these features are, they are not acci- dental, but of such constancy as to admit of no hesitation in accepting the conclusions to which they point. The length of the ray cell is subject to considerable variation not only within the limits of an individual but also between one si^ecies and another. Our studies, however, do not permit the formulation of a law applicable to specific differentiations, even If such a law loes exist, which present evidence leads us to doubt • but det- of length, in terms of spring tracheids, have been incorporr . m all the diagnoses, since they are often very suggestive and thus may assist in the ultimate recognition of the species. The form of the cell is of more evident value, although too much stress must not be laid upon it. The cell is either straight as in Juniperus, Libocedru.s, or Picea (fig. 23), or it becomes tusiform through contraction of the extremities, as in Cupressus Sequoia, Taxodium, etc. (fig. 21). As a well-defined differentia! character its value is only one degree higher than the length of the cell, and for the ame reason it has been introduced into the diagnoses as a controlling fa^^or of secondary importance 'II CMAi'TKR VI MEDULLARY RAYS {continue,/) Rav Tracmkids In the higher Conifernc the mc(l"llary ray is distinguished by the presence of an element which differs materially in its structure from the associated jarenchyma < ells. These elements have been designated 's ray tracluids (13, 491-497). Their struc ture is so peculiar, and they present such important rebtions to classification and development that a somewhat detailed account of them is necessary, to some extent in recapitulation of well-known observations (13, 461 ; 81, 13 ; 82). As stated by Ue Bary, the ray tracheid resembles the paren- chyma cells, from which they differ, however, in the presence of bordered pits on all their walls. Furthermore such pits not only differ materially in form and size from the bordered pits of adjacent parenchyma cells, but they are always much smaller than the pits of those wood tracheids on which they border. Such tracheids are invariable features of the ray in all the higher Coniferac from Tsuga and Pseudotsuga to Pinus, to the extent of 25 per cent of the investigated genera. In Juniperus tb 7 occur very rarely, being found, so far as I am aware, in only one species (J. nana) out of a total of eleven, and they are so sparingly developed as to readily escape observation. In Thuya they are to be met with in T. japonica, likewise in a rudimentary state of development. Out of nine species of Cupressus they occur only in C. nootkatensis. Of the ten investigated species of Abies they are found only i onlsamea. In commenting upon this fact many years smce (13, 490), it was also pointed out that among European species A. e.xcelsa is similarly exceptional, but no attempt has been made to interpret the significance of such facts. 88 MEDUILARV RAYS «9 In Thuya. Cupressus, and Abies the tracheids are strictly mar- Kinal in the composite rays, forming the entire Htnicturc in ray^ only one or two elements high. This , elation obtains in all the higher Conifera; in the first instance ; but in I jrix, I'icca. and I'mus, where there is a notable increase in numbers, they also become mterspersed with the parenchyma cells and eventually predommate over them, a feature which is especially character- istic of the hard pines. Efforts have been ma le to show that in all such cases the two kinds of elements su .ed one another in a definite order from above downward, or . reverse, but our studies have failed to show that this is capable of practical ap- plication to the purposes of classification or even of phylogeny (13, 49I)- The pjeat fact of importance for our present purpose, howe-er, and one wl -h stands out with much prominence, is that the ray tracheids are ..ot a structural feature of the more primi- tive C oniferales, but only of the higher types, such as Picea and I'mus Furthermore the primitive position for these structures IS in the one- or two-celled rays, or correspondingly in the margins of the composite rays. In Thuya and Cupressus the tracheids appear to stand by them- selves, and they exhibit no special relations to the parenchyma elements which would permit of inferences as to their possible ongm. In the genus Pinus, on the other hand, where the rela- tions are somewhut complex, evidei.. does appf of such a nature as to suggest their derivation. In Pinus ino. P. Torrey- ana, P. pungens, P. clausa, P. taeda, R palustri.,, an J P. cubensis we frequently find thick-walled parenchyma o.As and characteris- tic ray tracheids conterminous ' ;,> one ano K. ;. This does not mean a simple association, sine jarly all such cases, as typ- ically presented by P. palustris, also show a graduated structure of such a nature as to confirm the belief that the one passes into the other by structural gradations. That such is the case can- not be doubted, and if further confirmation were n-eded, it is afforded by the precisely parallel relations to be met with in the formation of resin cells and resin canals. A further fact of much significance from the standpoint of development is that such go ANATOMY OF THE GYMNOSPERMS interchangeable relations are peculiar to the highest types of the genus Pinus. But we may ask, What is the function of these structures which make their appearance only in the higher Coni- fera; ? What is the proper significance of their appearance there, and do any other plants offer parallel examples ? In the so-called medullary rays of Lepidodendron selaginoides (81, 141) there are numerous reticulated or spiral elements which are undoubtedly of the nature of tracheids, and they may be held to represent theaucestral form of theray tracl eids in the Coniferae, toward which they bear the same relation that exists between the spiral protoxylem element and the characteristic wood tracheid with bordered pits. From this it is apparent that the ray tracheid of Pinus or Tsuga represents a primitive structure which reappears in response to conditions of growth and structural alterations of such a nature as to demand the interposition of more simple, because more primitive, elements for the proper performance of necessary functional activities. These activities, in the case of Lepidodendron, are probably expressed in the radial distribution of water (81, 141), and we are no doubt correct in assuming similar activities to be carried on in the higher Coniferae. In all those species which present the primitive structure of the thin- walled ray cells, both fossil and recent, there are no tracheids to be found. As a tendency to thickening of the wall arises, there is also developed a sporadic tendency to the development of ray tracheids, as in Thuya and Cupressus. It is also a noteworthy fact that simultaneously with a general thickening of all the cell walls throughout the ray, as in the genus Tsuga, ray tracheids become a constant and prominent structural feature. This rela- tion exists in Pseudotsuga, Larix, Picea, and Pinus, and it is a remarkable fact that as the type of organization advances, and the structural modifications of the wall become more profound, the tracheids gain steadily in numbers and importance until they finally replace the parenchyma cells more or less completely. Such facts serve to direct attention to the idea that by such pro- gressive alteration the ray cells gradually lose their normal functional powers with respect to the radial distribution of water, MEDULLARY RAYS g, and under such circumstances it is imperatively demanded that this deficiency should be met through some other structures Under these circumstances two alternatives are possible : first that the thick-walled and useless cells should return to their primitive condition in opposition to the general course of devel- opment, and once more resume their appropriate functions. Such structural reductions do in reality occur in these very cases, as shown in Pinus taeda, etc., but it is to be observed that they are of the nature of a growth which has been arrested at such an early stage as to be devoid of many of the normal structural features Furthermore it would be difficult, if not impossible, to obtain evi- dence from other plants in support of a hypothesis of this nature It is true that in the case of girdled pines the heartwood may resume an activity long since lost, and thus take upon itself once more the function of the sapwood, and also to some extent the function of the bark ; but such renewed functional power does not in any way involve structural modifications of existing elements, and cases of this sort cannot be cited in support of the hypothesis. It is therefore fair to conclude that such structural reduction and restoration of functional activity are accompanied by a partial diversion of energy to the preponderant tracheids. The second alternative permits us to consider that in the ordinary course of development the ray cells gradually lose their functional activity as a result of extreme structural modification, and that this loss of power cannot be restored, even though the wall may return to a primitive condition of structure through various phases of atrophy. In accordance with this idea the tracheid would be introduced as the most natural because the original medium for such activities as are centered in the ray, and it would therefore acquire additional importance both nu- merically and functionally in direct proportion to the loss of power experienced by the parenchyma cells. This appears to be a reasonable interpretation, and in the light of observed facts It would seem to be the correct one. A structural feature of great importance in the ray tracheid appears in certain inequalities of the upper and lower walls, which f 92 ANATOMY OF THE GYMNOSPERMS take the form of teethlike projections into the cavity (fig. 26). In what may be regarded as the most highly developed tracheids the teeth project across the cell cavity until they meet and coalesce, thereby forming a more or less definite reticulation, which gives to the tracheid a very characteristic appearance. As seen in tangential section, such reticulations often appear as narrow bands crossing the cavity from side to side, Vhys giving the cell a varying aspect. Such dentate and reticulated tracheids are absolutely confined to the second section of the genus Pinus, in which they constitute one of the most characteristic features to the extent of 68.3 per cent of the species. A more detailed analysis of this feature, as applied to the hard pines, is desirable. In P. resinosa and P. Thunbergii the tracheids are simply dentate. In six species, represented by P. Murrayana, the teeth extend into definite reticulations confined to the summer wood ; but in six other species, represented by P. Jeffreyi, such reticulations are sparingly developed throughout the ray. In P. taeda a transitional form appears. Typically this species shows the tracheids to be sparingly reticulated, but occasionally they are strongly reticulated throughout. This brings to mind the further fact that in all species which are sparingly reticulated there is a marked tend- ency to strong reticulation in the summer vvood. In the thirteen remaining species the tracheids are uniformly strongly reticu- lated throughout the extent of the ray, and this feature attains its highest expression in P. palustris and P. cubensis. It is there- fore manifest that we n'e to deal here with a graduated develop- ment of such a natLie that the simply dentate tracheid is the most rudimentary, while the strongly reticulated is of the most advanced type of structure. The value of the ray tracheid for taxonomic purposes depends upon (i) its occurrence in certain genera, and (2) its structural peculiarities. In the great majority of cases 1 e simple wall of the tracheid affords no basis of specific differeiitiation, but in the various forms of dentate and reticulated walls of the second sec- tion of Pinus it is of well-defined value in this respect. Pinus resinosa, P. Thunbergii, and P. koraiensis are all characterized MEDULLARY R^"S 93 by the occurrence of simple teeth, v/hich are sometimes sparingly developed. This feature is intimately associated with the occur- rence of large, simple, and single pits on the lateral walls of the ray cells. From this group P. densiflora may be differentiated by the reticulations in the tracheids of the summer wood. Among the hard pines P. taeda is distinguished by ray tracheids, which are typically sparingly reticulated throughout, but on the other hand P palustris and P. cubensis, which probably represent the highest types of the genus, are at once separated from all other species by reason of the extent to which reticulations ^re developed The relations which the tracheids bear to the parenchyma cells in the general composition of the ray also have an impor- tant bearing upon specific differentiations. In the genus Tsuga the tracheids are sometimes interspersed, affording the first instance of a relation which later becomes most prominent in the higher genera, and the same relation is also expressed in Pseudo- tsuga and I.arix. In Picea there is a somewhat stronger tendency to an mterspersal which is only expressed fully in Pinus. In the soft pines eleven out of thirteen species show, as in the previ- ous genera, that the tracheids. as a rule, are rarely interspersed; P. aristata forming a partial exception, as shown in a sparing in- tersixTsal. P. monophylla and P. monticola. on the other hanH show a strong interspersal of the tracheids, and in this respect they approach the hard pines. In the latter group we again find the first four species characterized by a rare interspersal ; but passing on to the more highly c'n'eloped species, such types as P clausa, P. palustris, and P. glabra show that the interspersed tracheids are not only numerous but also that they eventually become conspicuously predominant and often constitute the bulk of the ray structure. It is evident, then, that such features pos- sess an obvious value for diagnostic purposes, particularly in the genus Pinus, where the variations are numerous, well defined, and applicable to particular species or groups of species. As displayed in tangential section, the medullary ray exhibits two principal forms, each of which presents features of great taxonomic and phylogenetic value. The type of structure which 9^ ANATOMY OF THE GYMNOSPERMS prevails, and which may be regarded as the fundamental form of the ray, is that of from one to many cells superimposed in a single series of varying height (fig. 27). Such one- seriate rays are characteristic features of all the investigated recent genera. In 30 per cent of the genera there is a sporadic tendency to a multiseriate form as expressed in the devel- opment of rays which ire two-seriate in part. Such enlargement is not confined to any partic- ular portion of the structure, and within the limits of the same section it may arise at the cen- ter or at either end. It is never found in /\bies, Picea, or Pin us, but it is met with m Pseudotsuga macrocarpa, three species of Cupressus, two of Juniperus, one each of Sequoia and Araucaria, and two of Larix (figs. 27, 28). In Libocedrus such tendency is much more pro- nounced, and the rays may be described as two- to three-seriate in part. Fig. 27. Sequoia This feature is of so sEMPERviRENs. sporadlc a nature that showing a typically satisfactory evidence as to one-seriate ray of j^g origin or significance, broad form. >. 280 , , ^ but reference to Cordaites tends to throw some light upon this somewhat obscure problem. In fourteen species of Cor- daites, three of which are European (28, 606- 609), it is seen that the rays present four variants ranging from the strictly one-seriate form to one- to two-, rarely three-seriate. The distribution is in the following percentage proportions: Fig. 28. Taxus brevi Foi.iA. Tangential view of a medullary ray showing ics two- seriate character. X 280 1-2, rarely 3-seriate 21.4 percent I 2-seriate in part j-2, seriate . 14.3 " " I i-seriate . . 50.0 per cent 14.3 « « MEDULLARY RAYS 95 0 0 From this it would appear that Cordaites as a whole approaches the primitive, multiscriate ray, such as may be found in the Cycads, much more nearl> ihan any of the existing species under consideration, and from this point of view it becomes possible to arrange a sequence showing the relative development in the following terms: (i) Cordaites. (2) Libocedrus. (3) all other genera, as enumerated above. The evidence of fossil plants, however, shows that caution must be exercised in cur estimate of what constitutes the primitive ray. The structure of Stigmaria shows a preponderance of one-seriate medullary rays (81, 224), and that such are primitive rays cannot well be doubted. In general, however, we are pi - ably not far from correct in the assumptk.n that -.he highest form of the ray is expressed in if, one-seriate character. Deviations from this uould then require to be interpreted as vestigal features, which indicate a relatively lower ivpe of orgr-.nization in direct propor- tion to the increase of a tendency toward a multiseriate form. In the majority of species the side walls of the parenchyma cells are thick and traversed by small pits. In the genus Pinus the wall is commonly thin, and it closes the orifice of a very large pit on the wall of the adjacent wood tracheid. This is notably true of the soft pines, in which the .side wall either pro- jects as a convex membrane, or it is concave and curves into the cell cavity. Such a feature is of very little if any importance except in P. reflexa, where the thin side walls almost invariably project so as to give the cells a correspond- mgly mflated appearance (fig. 29). It is not only apparent in a tangential section, but is very conspicuous in the transverse sec- tion (fig. 1 8). where the inflated walls are seen to project into the '0. Fic. 29. Pi MS RE- Fl.KXA. Tangeii'ial .section of a r.iedui- lary ray slunvir, (he typically inrtated cells. X ^CX3 Jf M 96 11 £ f Fig. 30. PSEUDOTSUGA DouGLASii. Tangen- tial section of a fusi- form ray showing (a) the typical resin ca- nal with thick-walled epithelium, but devoid of thyloses. x 280 ANATOMV OF THE GYMNOSPERMS cavities of adjacent wood tracheids, thereby giving to the ray a beaded appearance. As an exceptional variation it possesses no ap- parent significance with respect to questions of descent. The second frrm of the ray is t'uit which has been designated as fusiform in refer- ence to its characteristic outline (44, 39). Such rays occur in relatively few of the existing genera to the extent of 20 per cent. They occur typically in Pseudotsuga, larix, Picea, and Pinus, and they are thus seen to be characteristic of the most ad- vanced types. Among extinct species they are unknown except in the case of Sequoia Burgessii (46, 42-46) and S. Penhallowii of Jeffrey (25, 321), in which they present a remarkable exception to the general course of development and structure of that genus. The fusiform rays are peculiar in their structural features. They vary greatly in height as between different genera, and such variations also occur within a given genus, the extremes being met with in the genus Pinus, where P. palustris and P. pon- derosa present the antithetic relations. In most cases they are much higher than the one-seriate rays with which they are associa ed, but this rule is subject to sev- eral exceptions. They are always distin- guished by a broadening of the central tract by from two to several times the original dimensions, thereby becoming more or less multiseriate. These variations depend upon the nature of the included structure, which exhibits modifications directly related MEDULLARY RAYS 97 to progressive development of the genus. Such broadening arises abruptly in Pseudotsuga, Larix, and Picea, so that the terminals above and below consist of a single series of cells with the general structure of the one-seriate ray (fig. 30). In Pinus the broadening is less ab- rupt, diminishing in both direc tions somv;what gradually, thus giving rise to a region of lenticu- lar form which occupies upwards of half th( height of the ray, or in son e caser, constitutes the entire atructunj. From this it follows that in such types as P. palustris (fig. 3 1, B) the termi- nals, which are often prolonged to gre-t length, may be linear and one-seriate, while in P. pon- derosa the whole ray is lenticular in outline and the terminals con- sist of only one or . wo limiting tracheids (fig. 32). Within the region oi the central tract the cells are all thick-walled in Pseu- dotsuga, Larix, and Picea, but in Pinus they are genen.lly thin- walled, and in the hard pines this fe- cure is emphasized by a degen- eration of the tissue to such an extent that it is readily broken P ~ " out in making sections, whence >-ic..3i,A. Pinus ALBicuALis. Tan- ;» ^i,„, *•.-,, genual section of a fusiform ray " Characteristically appears Stl VnTSVaT.i^rXcl'^'ut'ci '''^'! """"'^ ^'■°'^^" "^ °^ ^"^'''^ly parenchyma, x 280; B. Pinus pa- Wanting. The principal feature I.USTRIS. Tangential sm-lini. „ The term " equal " here applies to cells of the same ray which are of the same width, " uniform " to the cells of all rays which are pretty constantly of one form, the contrasting terms being " unequal" and "variable " respectively. MEDULLARY RAYS lOI Generic. diagnosis can be drawn ., ly when wc take cognizance of the principal aspects presented, nn.l these arc sometimes as many as four in number. ' A consideration of the various structural features thus dis- cussed m their relations to cbssification will show that no other portion of the stem possesses so many elements of importance as the medullary ray, which, in consequence, attains the highest value m this respect and affords differential characters of wide range, great prominence, and easy recognition, and is of primary importance in the differentiation of groups, genera, and species • and, as a general summary, the utility .,f these characters for such purposes is approximately indicated in the following tabulation : 1. Rays (tangential) of two kinds. 2. Ray tracheid.t apjKar in just those situations ; that when they arc iiioradic, as in Abies hal- samca, they are ;ntcrs{K'rsc'(l and conterminous with the marginal cells ; thai their external forms and general aspect are the seme ; and that when the trachcids are fully developed and become constant features of the ray it is at the expense rf the ordinary marginal cells, which then disappear. Furthermore Jeffrey has shown that in Sequoia Penhallowii (as), where the marginal cells assume a very characteristic form, they are also interspersed in the higher rays precisely as tracheids are in the rays of the higher Conifer.TB. Another feature of these cells — to which Jeffrey has directed attention in Sequoia Penhallowii ~ is the presence of numerous crystals. This is unique among the Sequoias, and it is unknown in any other genus of the Coniferales except Abies, where, as Jeffrey also shows, a similar deposit of crystals is to be met with in A. concolor, A. grandis, A. bracteata, A. nobilis, and A. magnifica; but it is a feature of much more sporadic occurrence, since large areas of these species show no t rystals, while in Sequoia Penhallowii they are exceedingly abundant. Jeffrey correctly regards this as indicating a certain relationship between these two genera (25). a connection, however, which is also indicated by other structural features, as pointed out by Penhallow some years since (44. 45). CHAPTER VII MEDUI.MRV RAVS {conHnurd) Relations to Development We arc now in a p<»»itk.n to determine the relations in which the various structural features of the medulLry ray stand to development, and for this purpose it may be most convenient to discuss them i-, that sequence which is apparently consonant with the general jrder of evolution of the entire group It has been ascertained that bordered pits are characteristic features of the lateral walls of the ray cell in 72.4 per cent of the investigated species. and that in theremaining27.6per cent.among the higher types, simple pits predominate, but a closer scrutiny of this latter group discloses some features of mo-e than passing .merest. Reference to the table of anatomical data (Appendix A) will show that the change from bordered tr simple pits is entirely confined to the genus Pinus. and that it does not arise abruptly as if m response to some unusual condition whereby a profound alteration in the usual course of develooment was iniuced • but ■t IS effected by stages, showing that whatever influen-^es were l>rought to bear, they operated gradually through a .newhat pro onged period of development, while here and there strong tendencies to reversion were manifested, and that the alteration was finally effected in a permanent way. only in the most highly cifveloped pines. Commencing with P. Lambertiana, it will be observed that some species of the soft pines are characterized by -".mple pits. Among the hard pines P. clausa and P. rigida have bordered pits, while the si.x following species again show simple P'ts. We next come to a group of four species, with one excep- tion (P. Murrayana) Japanese, in which there is a mingling of botli bordered and simple pits, showing a decided persistency 103 •■I ^ ,■ '■ ;■ - i ;.i *'' I". 104 ANATOMY OF IHE GYMNOSPERMS of the primitive character in the face of conditions which involve a change. Following these are two species with simple pits, one with transitional features, five with simple pits, one with bor- dered pits, one with the transitional form, and the remaining six species with simple pits only. It will therefore be seen that these changes occur in waves, and that within the limits of forty-one species there are three complete and six incomplete recurrent phases. If we were arguing from purely theoretical grounds, all of these species should be arranged in such order as to show (i) bordered pits, (2) transitional forms, and (3) wholly simple pits, and we should thereby gain a perfect developmental sequence. But such a position would not be justified by other evidence of an equally if not more weighty character, and it is our object to interpret the facts as they arc found. It has already been shown that the occurrence of simple pits in the pines is conso- nant with a higher type of development, and that the change is not only accompanied by sporadic reversions or survivals, as one may choose to regard them, but that the change as a whole is a process of reduction. From this point of view, then, we must regard the occurrence of bordered pits in P. clausa, P. rigida, and P. pungens as pure survivals of a more primitive structure, — a feature which is less perfectly expressed in such transitional forms as P. koraiensis or P. inops. But a mere mingling of the two kinds of pits in the same species is not the only evidence in this direction. The mingling of simple and bordered pits does nut occur indiscriminately, but in accordance with a well-defined law to the effect that the former are characteristic of the spring wood throughout its entire extent, while the latter occur, if at all, only in the summer wood, where they might be expected, since tiic arrested development which might be complete in the case of relatively thin-wallcd cells could be readily overcome in part in walls of greater secondary growth. This in no way conflicts with the observed fact that in the majority of cases the usual course of development is such that the bordered pits of the spring wood very commonly become reduced to simple pits in the summer wootl, in accordance with De Bary's law, as already stated in MEDULLARY RAYS »05 application to other cases. Constancy in the structure of such pits has been found to be characteristic of Cordaites, Gingko the laxacea-, and all the lower forms of the Conifera.. from which we may conclude that the bordered pit is essentially a primitive character. On the other hand, variation is a well-marked feature of the pit m the genus Pinus, as first e.xpressed in the large oval or squarish and open pits of P. resinosa or P. Thunbergii, and as later appears with greater frequency in the smaller and very inconstant pits of P. ta^da or P. palustris. Such variations, then, involving a gradual and complete transformation to the condition of simple pits, are characteristic only of the more highly developed pines, from which it may be concluded that it is a feature con- sistent with a relatively high order of development in exact accord with the principles governing parallel changes in the pits of the wood tracheids. They are also in harmony with the well-known principle that variation is always of a more simplified form in primitive types, but that it tends to greater diversification with advance in organization and general development, as a necessary sequence to the adjustment of the organism to a wider and more complex environment. Finally, it has been shown that the elimi- nation of the bordered pit proceeds concurrently with the more complete organization of the ray tracheids. in response to a sub- stitution of functional activities between these structures and the degenerate parenchyma cells. We may therefore conclude that extreme variation in the character of the pit is an expression of a liighcr type of development, and that from this standpoint such structures have a definite value in solving questions of descent. I he terminal walls of the ray cells present three variants with ■xspcct to secondary growth. All the more primitive Cordai- tales and Coniferales are characterized by thin walls. Cupressus and Juniperus are chiefly distinguished by their thin walls, which arc also locally thickened, a feature which has been shown to be due to incipient secondary growth. But such alterations are already foreshadowed in Liboccdrus, where the local thickening of the wall is of a sporadic nature. In Abies magnifica and A. i^^andis there is a partial recurrence of thin and locally thickened h % 1 06 ANATOMY OF THE GYMNOSPERMS walls, which is pretty fully expressed in A. concolor. A similar recurrence is met with in Pseudi)tsiiga macrocarpa, in Picea polita, and in Pinus Parrayana, and it is also complete in thirteen of the most highly developed species of Pinus, where the walls have suffered extreme degeneration. Within the limits of Picea (i) and the soft pines (5) there are six instances in all of spo- radic and partial survival of the thin and locally thickened wall. The first tendency to thick and strongly pitted walls is mani- fested in five species of Juniperus, and such development is fully expressed in what may be regarded as the three most highly developed species. Thick walls are then fully characteristic of Abies, — with a partial reversion in A. concolor, — of Tsuga, Pseudotsuga Douj;'asii, and Picea, with the exception of P. polita, five species of soft pines, and three species of hard pines. In P. toeda and P. pauistris the walls are so degenerate that their structure cannot be satisfactorily determined, but they arc pre- sumably thin-walled. From these facts it is manifest that the progressive thickening of the terminal walls accords with the general course of devel- opment, and once more making use of tne principles already applied to the pits on the lateral walls, we are brought to the natural conclusion that (i ) an increase in the thickness of the walls is evidence of a higher type of organization, and (2) that the sporadic recurrence of thin walls with local thickenings represents the persistence of a primitive character. Ray tracheids probably constitute one of the most valuable of the structural elements as an indication of development. This has its foundation (i) in the fact, previously shown, that they arise as secondary structures from the parenchyma elements, with which they exhibit interchangeable relations, in direct re- sponse to the requirements of a higher degree of organization, and (2) in their general relation to progressive development. The complete absence of ray tracheids from the Cordaitales and Gingkoales, as also from the Taxaccae and more primitive Coni- fera?, while they arc invariable features of the higher Conifera-, MEDULLARY RAYS 107 in which they attain their most complete development, admits of only one mterpretation. The fact that they are exclusively features of the Conifera. emphasizes their inferior value for Z termmmg the derivation of that group, while it points to their supenor importance as a factor in the sequence oi the various coniferous genera. They occur sporadically in Thuya (,) Cu- pressus (3). Juniperus (,). and Abies (1). They are prominent features of Tsuga. Pseudotsuga. Larix, Picea. and Pinus. Thei invarable absence from Sequoia would appear to suggest that this genus ,s more primitive than Thuya, but there are other reasons which serve to suggest the opposite relation. Apart from this exception, it will be seen that in accordance withVhe relations exhibited in the table of anatc.mical data (Appendix A) the genera enumerated form a continuous series, commencing ..th those showmg sporadic tracheids and ending with those in which such structures attain their highest expression. From this we are justified in the conclusion that the rare occurrence of tracheids in Thuya, etc.. is to be interpreted as the first evT dence of a tendency in development which is only fully realized at a later period, and this appears to be justified by a closer exammation of the last five genera in this respect, since it is found that in them the tracheids not only show a progressive numerical development but their structure likewise becomes more complicated in direct relation to the evolution of higher ypes of genera and species. We must therefore I^ok upon the tracheids with their thin, simple walls as the .nmitive form. while those with the strongest reticulations are of the highest t) : , -he two being united by a transitional form characterized by the presence of simple teeth. The evidence at hand -'oes not appear to justify the idea that the various genera have been segregated into small groups representing side lines of develop- n^ent. but it rather favors the thought that each genus is in >t^^e.f a complete short line of descent, and that among these a prominent parallelism has arisen in the tendency toward the development of tracheids. -a tendency which has been carried to completion in the case of only five of the series, and in such m io8 ANATOMY OF THE GYMNOSPERMS a way that in only a portion of one of these has that completion reached its highest expression. The occurrence of two kinds of parenchyma ray cells is an exclusive feature of the genus Pinus, and its value for phyloge- netic purposes is strictly confined to the relations of the various species of pines. The first appearance of this differentiation is among the soft pines in P. aristata and P. edulis. It is to be observed, however, that the thick-walled cells are always domi- nant, the thin- vailed cells being interspersed amo-; met with. Such facts give effective proof of the belief that struc- tural alteiations of this nature are not only evidences of the highest type of development among the pines but also among the Coniferales as a whole. The invariable absence of the fusiform rays from all except the four genera which attain the highest structural development, and their constant occurrence in rxU the species of such genera, presents an argument of great force as showing their relation to the evolution of advanced types. There is here no evidence of sporadic development, foreshadowing the general course of evolution, but the fusiform rays with their resin canals appear abruptly and permanently. Among fossil plants — except the genus Pityoxylon, which, being essentially Pinus, falls under tlie general rule — there is no instance of such structures outside of the four genera named, save in the case of the remarkable Sequoia Burgessii, from the Lignite Tertiary (51, 42), and S. Pcn- hallowii of Jeffrey (25). As it will be necessary to further discuss the essential structure of the fusiform ray, we need not deal with it more in detail at the present moment. :rn CHAPTER VIII WOOD PARENCHYMA In our present studies we recognize as wood parenchyma all those elements which, in association with tracheids. hav. their major axes extended parallel with the principal axis of growth • and which, V accordance with accepted limitations, are charac- cr.zed by thcr more or less cylindrical form, abrupt termina- tions and relatively thin walls. Such elements do not occur in wood of the Cordaitales, and they are infrequent in the Ging- koales, but they are somewhat conspicuous features of the Coni- fcrales, where they acquire great prominence either because of thcr peculiar contents or their association with somewhat highly speca ized tissues. They differ in their structure as in their special unctions, though in the main they are connected with the production of resinous matter; and inasmuch as their mo^^t prominent feature is usually found in associated products of cel- lular activity, it will be most convenient to discuss them under specific names, which may serve to direct attention to their par- ticular purposes in the plant economy. They may therefore be classified as follows : j j ^ u^ Wood parenchjTtia : a. Crj-stallogenous i(''oblasts. b. Resin celLs. #S.S CrVSTALLOGENOUS J .OBLASTS The investigations of Eichlcr (15, 35) show that in Gin^' -^ the wood IS characterized by the presence of wood-parenchyma col s, which take the form of short idioblasts of lenticular form m longitudinal section, and are distinguished by the storage of crystals of calcium oxalate. Such structures are peculiar to this 109 no ANATOMY OF THE GVMNOSPERMS genus, in which they form a specific character of definite value, and it is therefore of importance that they should be described somewhat in detail. In a transverse sectioi (plate i8) the idioblasts, recognizable by their conspicuous crystals, may be seen scattered through the entire section without special reference to either the spring or the summer wood. Under a high t ^ree of amplification it will be seen that they are often single, but quite frequently they are grouped in radial series of ttvo or three, in which case one is generally much larger than the others (fig. 34, a). The form is narrowed tangen- tially and extended radially so ^ as to be approximately lenticu- a^'^^/iTT) Id'^\ ^^^' ^^^ ^^^ cavity is usually Wk^^L-^ Ik?J?^^' pretty well filled with a com- pound crystalline mass. The idioblast is situated in the line of one of the radial rows of tracheids, the continuity of which it interrupts. It is usu- ally much larger than the in- dividual wood trachcid, from which it also differs in the char- acter of the cell wall, which is very thin and not infrequently .shows a want of continuity suggestive of obliteration in the course of development. In a radial section the idioblasts are usually of an isodiametric form, more rarely elongated longitudinally, and the compound crystalline mass somewhat more than half fills the cavity. In this section the walls are seen much better than ir any other, and the relations of the idioblasts to one another are well exhibited. In a tangential section (fig. 34, l>) the wall is also well displayed. The individual idioblasts are lenticular in form and the crystalline mass completely fills the cavity transversely, ikai- Fig. 34. GiNcvo niLOBA. a, trans- verse section showing the occurrence and form of a crystallogenous idio- blast ; i, tangential section of the same, tr., tracheids; /r.ii'., tracheid walls; /., idioblast; iw., idioblast wall; i>:, crystals, x 233 RESIN CELLS ,,, but only about half fills it longitudinally. This section is the most useful for displaying the relations of the idioblasts to the adjacent tracheids, inasmuch as the limits of the walls of the latter are much more clearly defined. As seen i.. the tange ial section, the Idioblasts fall into a single longitudinal series, which may not embrace more than two or three members, but more commonly there are upwards of twency^ne in a series. Not infrequently the Cham of crystals will be found to be interrupted for some httle distance, but the continuity of the idioblasts will then be seen to be uninterrupted through the development of cylindrical elements of uniform but smaller diameter and devoid of crystals from which it would appear that the lenticular or rounded form! as determined by the particular plane of section, is not the normal form of the cell, but that such special form results from the growth of the crystal, which must have been deposited when the tissue was in a formative stage of development. This is made apparent in another very striking manner. In any tangential exposure of such a series it may be seen that the terminal mem- ber does not necessarily occupy all the space between the walls of adjacent tracheids. There is thus developed an intercellular space of variable dimensions, which may be quite small or may be so extensive as to suggest that the crystals were formed in such spaces and not in closed cells. Such spaces are obviously not the result of that splitting which is ordinarily incident to the growth of tissues, but they clearly arise as a secondary effect incident to the development of the crystalline mass and the pressure of this latter upon the surrounding parts. Resin Cells' In a large proportion of the Coniferales the wood is character- ized by the presence of more or less numerous wood-parenchyma cells. The.se are always distinguished by their cylindrical form and transverse terminations. They are invariably associated with the production of resin, either as entering into the com- position of resin passages or as isolated cells. It is this latter 112 ANATOMY OF THE GYMNOSPERMS group with which we arc most particularly concerned at the present moment, and as, with very few exceptions, they are uniformly characterized by the presence of resin, which gives them a distinctive appearance, I prefer to describe them as resin cells rather than by the more commonly employed designation of zvood parenchyma, which conveys no suggestion of their special function and most prominent feature. The resin cells are found to be entirely wanting in those species of Taxus (4) and Torreya (3) which are included in the present studies. They do occur, however, in Podocarpus, where they present the usual structural features, but they are there remarkable for their number and the great abundance of massive resin which they contain. This distribution in the Ta-xaceae does not altogether accord with the conclusions of Eichler (15, 35), who states that they occur very sparingly in the Taxaceae, but makes no mention whatever of their presence in Podocarpus, where they are much too prominent to escape even the most casual observation. In the Conifer.x resin cells are characteristic of all genera except Picea and Pinus, where they are replaced by resin pas- sages, of which they form essential parts. They are, therefore, features in the wood structure of twelve genera, and they are constant characteristics of all their species, with very few excep- tions. Such exceptions apply exclusively to the genus Abies, in which four species — A. Frascri, A. lasiocarpa, A. Veitchii, and A. balsamea — are wholly devoid of such structures. The recognition of the resin cells presents no difficulty in the great majority of cases, because of the abundance and depth of color of the resinous contents. This finds its most complete- expression in Taxodium, Sequoia, Cupressus, etc. In Abies, on the other hand, where these cells have experienced extreme numerical reduction, and where there also seems to be a cor- responding reduction in their secretory power, it is impossible to recognize them in this way. In such cases it is often pos- sible to distinguish them by their slightly different form and somewhat thinner walls as compared with the adjacent wood RESIN CELLS "3 tracheids, by their situation slightly in advance of the outermost row of summer wood tracheids. and most particularly by their pitted terminal walls when the latter lie near the pbne of sec- tion. This last feature may also be relied upon in all other cases when any element of doubt is involved (fig. 35) in longi tudinal section the characteristic form of the cell serves to dis tmguish it beyond all doubt, even in the absence of resinous contents. Whether exposed in radial or tangential section the cell has the form of a narrow cylinder upwards of 300 m in length and always several times longer than broad, except in cases where F.o. 35. AB.ES AMABius. Transverse section showing .he position and structure of the resm cells (r...) on the outer face of the summer wood, x joo there is a definite tendency, through aggregation, to the forma- tion of resin canals. The resin cells sometimes occur in pairs, but more generally as isolater' structures separated by one or more tracheids The termmal \valls are transverse and more or less strongly marked with simple pits. The side walls, especially the radial, are pro- vided with simple pits, though often few in number, and this eature serves to a large extent to assi.st in their differentiation from adjacent tracheids of similar form (fig. 36, r). It neverthe- less not infrequently happens that in transitional forms, such as are met with in Sequoia sempervirens (fig. 36, c), bordered pits occur on the lateral walls. The resin is in all cases massive and often very abundant In such genera as Taxodium (plate 30) or Sequoia (plate 36) it is**"! 114 ANATOMY OF THE GYMNOSI'KRMS completely fills the entire cell cavity, but in I^rix, Tsiiga, and Pseudotsuga it takes the fornt of a pcriphctal layer in imme- diate contact with the inner face of the cell wall (plate 44). The reduction thus indicated is, in some species, carried to such an extent that the resin is barely recognizable, while in Abies it is wholly wanting. A relation of more than ordi- nary interest is that of the resin cells to certain forms of tracheids. In Se- quoia scmperv'ircns it commonly happens that the resin cells lie in immediate con- tact with tracheids ot special form. These structures are wholly unlike the wood tra- cheids among which they are found, but they are, in all essen- tial respects, like the tracheids of the med- ullary rays. They have the form of long, cylindrical elements with abrupt termina- tions, and they thus bear an external re- semblance in form to the wood-parenchyma cells with which they are associated. They differ, however, in the distinguish in;,' presence of bordered pits upon their side and terminal walls (fig- 37> «)• The relation of these two elements is nevertheless a much more intimate one than is implied by mere association. In Sequoia an interchangeable relation is manifested, as already pointed out, in the occurrence of resin cells with bordered pits Fig. 36. Sequoia sem- PERVIRENS. Kadial sections showing () resin cells from the spring wood showing the form of the resin ; (<•) resin cells showing transitional forms with bordered pits, x 200 RESIN CELLS "5 (fig. 36). while ,n Abies amabilis (fig. 37) resin cell, and tra- cheids al«. form a conterminous scries. It is thus obvious that we have here precisely the same interchangeable relations that have been found to occur in the medullary rays, and it is evi- dent the one element must arise through modification of the tl\J P"-^^;** order of this sequence is not altogether clear from the available data, but the fact that ray trr ' Ms are derived from their asso- ciated pau.ichyma cells, and that in such types as Podocarpus, Taxodium, etc., the resin cells occur without tracheids, while the latter do occur in Sequoia and espe- cially in Abies, scorns to justify the infer- ence that here also they a-e derived forms, having their origin substantially in special modifications of the parenchyma elements. In view of these relations it is necessary to distinguish such elements as parenchyma tracheids in order to establish their proper identity and differentiate them from the wood tracheids which have a wholly dif- ferent origin, as well as from the ray tracheids which have a wholly different location. It is probable that the paren- chyma tracheids also serve a similar pur- pose to the ray tracheids with respect to the distribution of nutrient fluids. The origin of the parenchjma tracheids as sug- gested finds support in the statement of Kichler (is) that the wood parenchyma arises through the activity of the cambium cells, abundantly in the Cupressinea; and Abie- tineas, formmg in exceptional cases the epithelium of the resin can -lis, since it at the same time shows how the parenchyma tracheids arise, and how they may be intimately connected with the wood parenchyma ; but it finds additional support in a knowl- edge of the genesis and structure of the resin passage. Fig. 37. Abiks amahii.is. Radial section showing (a) the structure of the parenchyma tracheids; ((*) the structure of the resin cells ; a and b being normally conterminous. X 2CX3 a- i\ Il6 anatonIy ok the (;ymnosi'krms In Sequoia and Abies we have two genera which arc remark- able for their transitional forms of structure, affording a fairly cle;ir conception of the genesis of the resin passage. In each case there is a well-defined tendency toward the aggregation of the resin cells into compact groups which take the form of lon- gitudinal strands, inclosed on all sides by the accomfxinying iwrenchyma tracheids. Under such circumstances the individiuil cells undergo a continual reduction in length until they eventu- ally become but two or three times longer than broad, or they may even become isodbmetric. This change is not accompa- nied by any alteration in the thickness of the walls in the earlier s .« of development, but as a result of such a shortening the effect is to bring about the concentration of a greater number of simple pits within a given area. Such cells, therefore, are always more strongly pitted than those which are isolated and of grc«ater length. When aggregates of this sort have attained to a certain degree of development a line of cleavage arises in the center of the mass and results in the formation of an inter- cellular .space which, according to ICichlcr (15), always arises schizogenously. This space is short and either isodiametric or but little longer than broad, the length coinciding with the prin- cipal a.xis of growth. Such cystlike reservoirs or sacs represent the primitive form of the resin canal, aufl t^^v arc typically developed in Sequoia, Abies, and Tsuga. They always fcjrm a continuous series extending in a direction jjarallel with the axis of growth ; but as the type of organization advances, they merge, forming a continuous canal such as may be f<>und typically in Pseudotsuga or Pinus. From these statements, then, it is clear that the parenchymatous resin cells undergo modification in two directions, passing into parenchyma tracheids on the ont hand, and on the other becoming shorter and shorter, according to conditions of aggregation, until they pass into .short cells which eventually constitute the epithelium structure of the somewhat complicated resin passage, the latter thereby becoming the ex- pression of a peculiar aggregation of resin cells. Whatever the stage of development may be, the resin passage is always RKSIN CKILS found to he composed of 117 ictiiral elements arranged in the lunowinK or.icr lr.>m without t.,ward the center : (,) mrcnchvma trachei,ls. (.) rein cells eventually forming an epithelium/and (3) the central reservoir i,. the form of a cyst or canal This structure .s fully exemplified in the genus Pinus. where the highest form of development is attained While the occurrence of resin cells in particular genera is a feature of great taxonomic value, their importance in this res,)ect .s greatly emphasized by the particular form of their distribution and the constant tendency they exhibit toward the formation* of definite aggregates. In Thujopsis (plate 24) and Crypto- merui (plate 26) the resin cell , are always scattered through- out the entire transverse secti and they show no tendency to the ormation of aggregates. ... I'odocarpus. where there is a notable increase in numbers, the same general law of segregation prevails, but there is nevertheless a somewhat well-defined tend- ency toward aggregation. In Thuya 66.6 per cent of the s,,ecies show definitely scattering cells. 33.3 per cent show the cells to l.e scattering with a tendency toward a more comjKict dispo- sition, while in 33.3 per cent the cells fall into well-defined aggre- gates or an approximation to such an arrangement The genus Sequoia IS characterized chiefly by the widely scattering distri- biition of the resin cells (plate 36). but in S. sempervirens there are indivdual cases in which there is also a definite aggregation 'nto groups. In Cuprcssus 53.9 per cent of the species are dis- tmguished by the presence of widely scattering cells, which be- come definitely arranged in zones m 38.4 per cent, and aggre- gated into groups in ^7 per cent of the species. It will be observed here that this feature of distribution is. on the whole more pronounced in the relatively primitive genera, and that it' diminishes in force in the genera of a relatively high order In Taxodium (plate 30) and Libocedrus (plate 32). both of which are distinguished by the presence of very prominent resin cells, these structures are disposed in well-defined . >nes which are concentric with the growth rings and lie either in the spring or summer wood, or in both. This is to be interpreted as a definite h Ii8 ANATOMY OF THE GYMNOSPERMS tendency to aggregation, which is nevertheless not fully expressed, since in each case there are numbers of cells which are not zonal in their distribution, but which conform to the law applicable to Thujopsis and Podocarpus. In Juniperus the cells are typically zonate, being also scattering in only one species. In Abies only 63.6 per cent of the species bear resin cells. These are neither scattering nor zonate in the sense of the previous types, but it is to be observed that in 50 per cent of such cases, or in 36.3 ^ per cent of all species, they are aggregated in groups as a pre- liminary step to the formation of resin passages. On the other hand, 36.3 per cent of all species show the resin cells to be few, inconspicuous, nonresinous, and scattered along the outer face of the summer wood. This, for reasons which will appear more fully later, is to be regarded as a phase in distribution leading to the final obliteration of such structures, which is fully accom- plished in 36.4 per cent of all the species as represented by A. balsamea, A. Fraseri, A. lasiocarpa, A. Veitchii. This last form of distribution is wholly typical of Tsuga (plate 44), in which there are no other resin cells than those on the outer face of the summer wood. Finally, in Picea and Pinus there are no separate resin cells in any of the situations described, since they have been completely replaced by highly organized resin passages. It thus appears that the distribution of the resin cells presents four variants which bear a direct relation to the organi- zation of resin passages, as the latter eventually replace the former. These facts will appear somewhat more clearly from the summary in the table on opposite page. p-rom such data it is clear that the distribution of the resin cells bears an important relation to the recognition of subgeneric groups and even of species. But viewing these structures from the broader standpoint of the Coniferales as a whole, it is obvious that they must be placed anion-,^ the structural elements which belong to the first rank for ta.xonomic purposes. We are now in a position to determine what relation, if any, such resin-bearing elements bear to questions of phylogeny, and we may first of all consider the resinous tracheids. These RESIN CFAAJS Percentage Distkibition ok Rksin Cells 119 NiMBRK OH Shecce Pkk IKNTo ' j .SlATTEK- 1 t)N THE OlTBu ■> (KH'KKENCl ISG In Zones (■KiUl'EnI Fa'. <»™, involving all three modes oTStir iTts "Th^^ IS an obvious tendency toward the elimination of ,L re *^ 1' ,s «: r ^^"'^ ^'"""O '" """■^- -- con«S tolS K=sin"i,:arU;:s-t\hirfr«fr-r::i ^pcAs This r *""'""'™ P'"=«eii 124 ANATOMY OF THE C.YMNOSPERMS more or less extended and continuous compound reservoir, lying tangential!)-. In their most rudimentary forms they present the aspect of simple aggregates of resin cells without any differen- tiation of a resin sac or of an epithelium. In a more advan :ed stage of development there is produced a central cavity in the form of an intercellular space (fig. 38, C) which has obviously originated schizogenously. About this the resin cells are gen- erally flattened radially and disposed in such a manner as to suggest the future development of a definite, limiting layer or epithelium. In the MR. r~\V (k. completed form of the structure the central space has broadened out and taken a cir- cular form, assuming the character of a defi- nite cyst bounded by as definite a limiting epithelium in which the cells are always flattened radially and disposed concentric- ally (fig. 38, Q. E.x- ternally to these cells there may be a second layer of similar resin cells, constituting the outer epithelium, while the whole is inclosed on three sides by a layer of parenchyma tracheids which arc exceedingly like the associated tracheids of the spring wood, but from which they may usually be distinguished by (i) their greater size and relatively thinner walls, and (2) the occurrence of bor- dered pits on the tangential and terminal as well as upon the radial walls. Such parenchyma tracheids never occur in the adja- cent summer wood for very obvious reasons, but on the radially opposite side of the reservoir they are very commonly flattened radially (fig. 39), and they not infrequently present the same ■■■sw Fig. 38. Sequoia sempervirens. Transverse sec- tion showing two contiguous resin cysts : C, com- pleted and with a normal epithelium {E.) ; C.\ an intercellular space as the rudiment of a cyst with imperfectly developed epithelium ; M.K., the medullary ray ; S. IV., the summer wood, x 225 RESIN lASSAGKS "5 structural aspects as the epithelial cells. The interchanirpnhin relafon between resin cell and parenchyma trLhe^as Cd^^^ shown would lead us to suspect a substitution in the con^pos t oi of the epthehum, and such substitution does actually occur Tee . IS often to be noted that the second and third rows iTbe made up, at least in part, of tracheids ^ thJ?ol!T''"'''"?' "'''' '''^'"" ^'^^ '■^^^"'"•^ •« f«"'«> to have theformofasacof vary ^g form and size, but generally elongated which contains "in l^do; 1 l^rct " ^T'^i '"^ "'^'"^^•■' <'^')- ""^ "' cell; the parenchyma (/no x 3^ ' """"' ''""" ^" ^'^'"''^"""' cndf lto^''T^" ^'v,^"''' ^"' ^^'"•^'^^^^y ^^«-^ ^^ both limi s^of'th?" '^"n'''"'"' "'''^' i'^'^ediatcly defines the gated bang several tm.es longer than broad. Beyond this, the be when' """T P^'-^"^^^"'^ t-^heids, readily distinguish- ble whenever the terminal walls lie near the plane of section, or herw.se recogmzable, as already indicated. Certain deviati;ns trum this typical structure require examination. The resin sacs ! lit i 126 ANATOMY OF THE GYMNOSPERMS arc p' intei onl; the tra ^MT 'd in vertical series of indeterminate extent, but at varying (if such a nature that they may sometimes be separated a rather thick wall of shori resin cells. At other times J somewhat distant and separated by an extensive vertical jf resin cells. From this it is obvious that in any given plane of section then will be a great diversity / Tv \ \\ ^^ of aspects presented, but I y%--fA \J)p^q C^ in the main exhibitinj; IL^( />» \> r-\\ \^^~^ structural gradations in the development of the reservoir, as already re- counted. In some cases thick-walled cells of cir- cular outline may be seen in transverse section to stand out from the [;en- eral line of the epithelium and lie within the cavity proper. More rarely such cells are so multiplied as to fill the entire cavity, and they may themselves be filled with granular resin. Such features arc clearly defined (fig. 39), and it is evident from the way in which such cells originate from the epithe- lial cells that they are of the nature of thyloses. A longitudinal section through such a reservoir (fig. 41) shows how such thyloses occupy the entire cavity of the cyst, while in other cases they may be purely local /fig. 40). Among fossil Sequoias similar thyloses form a most characteristic feature in the resin passages of the medullary rays in S. Burgessii and S. Penhallowii. Fig. 40. .Sequoia SF.MPERViRENs. Radia' sec- tion of a resin cyst sliowing the epithelium (£•/.) ; the central cyst (r.) with a thylosis (t/i.) ; parenchyma tracheitis (/•r.t.), and a tracheid of the lipring wood {Sp. T.). x 300 RKSIN PASSAGES III 127 ^P In Tsuga caroliniana there are no secretory reservoirs but just in the regioi. between the spring and summer wood of the same growth ring there are pccuhar aggregates of resin cells of a more or less rounded outline, forming a continuous series of considerable extent. An analysis of these aggre- gates shows them to be comjwsed of thick-walled and rounded resin cells, among which there may be a small central, intercellular space without any definite organization of epithe- lium. In such aggregates the com- ponent cells are far less resinous than the isolated re.sin cells of the same section. The parenchyma tra- f/>. cheids are not clearly distinguishable from the associated wood tracheids. In radial section the cells are seen to be very variable, thick-walled, and -sometimes with more or less promi- nent intercellular spaces. Between the rays they are several times longer than broad, but opposite the rays they are short, cylind jal, and more copiously pitted ; while sometimes they may be se. to merge into ray elements and thus to continue their course at right angles to their pri- mary direction. A careful compari- F„;.4,. .sk-,, .a .sKMr,.Kv,K.Ns. son of these cell aggregates with '**'^''*' '''' "" "f a f'^'^in lyst those of Sequoia and Abies leivcs '*';"«'"'?""- epithwium (<•/.) and llttle room for doubt as to their StrilC- P'«^tely fill the cyst, and .several tural and .'jnctional identity, and we "^ "'""'' '"''' ''-■■*'"»"'*• ^ "5 cannot do otherwise than conclude that they represent the most primitive structural condition which is capable of directly giving h \ 138 ANATOMY OF THE G.MNOSPERMS rise to definite cysts by central cleavage, and that such cysts are precedent to the formation of canals. In Tsuga Mertensiana the secretory reservoirs are disposed like those of Sequoia, on the outer face of the summer wood, where ^hey form tangential scries. They exhibit all the grada' tions from simple cell aggregates without a central space to per- fectly formed cysts with a definite epithelium. This latter is in one, more rarely in two, rows, and it is composed of more or less rounded or radially flattened elements. The parenchyma tracheids are few in number, and they are not readily distinguishable from the adjacent wood tracheids. In longitudinal section the reser- voirs are variously rounded or oblong cysts, contiguous or isolated and forming a longitudinal series. In their general form and structure they are essentially the same as in Sequoia. In the genus Abies secretory reservoirs occur in at least tour species, where they form more or less extensive tangential series, within which they are usually contiguous and more or less con- fluent. They present the same general variations in structural organization as in Tsuga and Sequoia, but in A. concolor, and less cnspicuously in A. nobilis, they are often extended in a radnl ,'nr, :tion so as to become narrowly oval or oblong and several times longer than broad. The epithelium consists of a well-defined structure composed of from one to three rows of cells. The first row, immediately bt^rdenng upon the canal, consists of rounded or oval and thick-walled cells, which are much smaller than those of Sequoia and similar to those of Tsuga. They arc- always characterized by an abundance of strongly defined, simple- pits, and many of them contain resin, which usually takes the form of rounded granules of diverse sizes. The parenchyma tracheids are so nearly like the accompanying wood tracheids as, m some cases, to be separable with some difficulty, but they gen- erally surround the resin sac, at least within the limits of the spring wood, and they not infrequently replace the parenchyma cells of the epitheHum more or less completely. Not infrequently they form somewhat extended radial series from the epithelium mto the spring wood, as in Picea (fig. 43). In such cases they are RKSm PASSAGES ,, ■n the case of A concolor, in which species they al essent allv If c* m .ho Cher f„rm,„g a ,is,„. which nearly fflW ,hc .n.ije regions or Sequoia and Tsn,a MerS^^^e ^he 1""' ff«« wh,ch are generally eharactcristic „f Tsuga JartlST The .nner epithelium usually consist, of short c^'S and strongly pitted cdls, which in the second and third !T »e hen replaces the other. The parenchyma trached. 1 Lh are always most characteristic of the spring wood ;„ , istingnished by the presence of large IdTrlSn'LS From these fact is clear that the secretory reservoirs of Lcs whTchTV" r'? ^'"">' '"'<' '"= 'oZo^'Z^ sacs, „h,ch De Bary has already pointed out a, a feature of f-' 130 ANATOMY OF THK C.YMNOSPERMS certain Conifcrac (18, 440), and in order to clearly differentiate them from those which occur in the genus Pinus I shall reserve for all such cases the term resin cyst. While such cysts arc typically developed in the three genera named, they are also features of Pseudotsuga, Larix, and Picea, — in fact, of all those genera in which the epithelium is composed of thick-walled cells, — but in these latter cases there is the additional feature that such cysts are always accompanied by the occurrence of similar structures in the medullary rays, and therefore they are asso- ciated with fusiform rays. From these facts, then, it is obvious that we have here a group of six genera all characterized by the presence of structurally similar resin reserve rs, but scjia- rable into two groups through the absence, on the one hand, and presence, on the other, of fusiform rays. That such saclike reservoirs represent the primitive form of the resin passage scarcely admits of question when we observe the various transi- tional forms which they present, and the relation which they bear to the resin passages of Pinus, — a view which is strengthened by the observation of De Bary (13, 443) that primitive forms of the secretory reservoir occur in the pith of Gingko in the form of elongated sacs. De Bary has shown that (13, 440) the secretory passages traverse the wood longitudinally, at first as prismatic tubes, which usually acquire a round or elliptical transverse section. In its strict sense, this statement is applicable exclusively to the genus Pinus, but inasmuch as there are important structi'nl gradations whereby Pseudotsuga, Larix, and Picea represent un intermediate type, while Pinus represents a completed type, it will be necessary to compare them somewhat in detail. In the genus Pinus, however, the secretory reservoir differs from that of all other genera, in that it consists of a definite and continu- ous canal of indeterminate length, and for the purpose of differ- entiating it from other forms I shall reserve for it the appropriate and long-used term resin f is sage. In Pseudotsuga the resin cy.sts are always scattering, though they frequently occur in tangentially extended groups of two or RKSIN PASSAG^:S «3I four contiguous or even coalesccnt reservoirs. The central canal. which is usually small anil not infrequently very narrow, is rather more generally rounded than in previous types. The epithe- lium is very clearly defined and consists of opt- to three rows of thick- walled parenchyma cells, sometimes containing resin, the first row of which are rather small and radially flattened, but in P. macrocarpa they arc rather thin-walled. In P. DouKlasii the epithelium is commonly extended on the two sides of the resin canal in such a way as to form a tangentially elongated tract which not infrequently extends beyond and involves neigh- boring medullary rays. In P. macrocaqKi, on the other hand, the epithelium is concentric with the canal, thus forming a tract of aljout equal thickness all around. Such a deviation as is expressed in P. Douglasii constitutes the first evidence of a tendency in development which is fully and frequently expressed in Pinus. Thyloses are of infrequent occurrence, and apjx:ar to be confined to P. macrocari)a where they are few in number and generally rather thin-walled. Parenchyma tracheids are usually not apparent in a transverse section. This results from the frequent IcK-ation of the resin passage in the summer wood, which is not favorable to their development, and from the close resemblance which they bear to the tracheids of the spring wood ; and while such elements form an integral part of the resin cyst, their particular disposition cannot be exactly defined, though there is no good reason for supposing that they differ in this respect from what may be observed in other cases. In a longi- tudinal section the canal is found to be more or le.ss continuous, though it presents frecjuent constrictions and is thereby reduced to very narrow dimensions, or it may even be discontinuous and thereby form cysts. It is this feature which causes the canal to exhibit such marked variations in size, when seen in transverse section. The epithelial cells are narrowly cylindrical and rather limg and thick- walled, as well as somewhat strongly pitted. Out- wardly they become much longer and relatively narrower, and they eventually merge with the surrounding {^renchyma tra- cheids, by which they may also be replaced (fig. 42). 1 #i 132 ANATOMY OF THE GYMNOSPERMS In Larix the same features of contiguity and coalescence may be observed, except that in L. occidentalis the resin passages sometimes form into continuous zones of imperfectly organized structures with the aspect presented in Tsuga Mertensiana. The epithelium is always well defined (fig. 42), and it consists of one, sometimes two, rows of cells. The cells of the first row are small, very variable in form and size, thick-walled, and more or less strongly flattened radially. They are also commonly resin- ous and more or less strongly pitted. When there is a sec- ond row of epithelium the ceils are essentially like the wood tracheids, and like the paren- chyma tracheids, from whicli they may be separated witli difficulty. The latter, there- fore, which are absent from the summer wood, can be distin- guished from the elements of the spring wood only when the pits on the terminal walls (fig. 42,/r.A) are brought into view, or, more rarely, when the pits on the tangential walls are in evidence. Thyloses rarely occur, and so far they have been noted only in L. occidentalis. where they are infrequent and thick-walled, and in L. americana, where they are of rare occurrence and thin-walled. In longitu- dinal section the central canal is always continuous, though con- stricted at intervals, a feature in all essential respects the same as in Pseudotsuga. Radially the first row of epithelial cells art- short cylindrical, or in L. occidentalis short fusiform, but there i< a graduated increase in length outwardly, so that in the second sza Fig. 42. Larix occidentalis. Trans- verse section from the inner spring wood sliowing a pair of resin passages with the central canals (c.) ; the thick- walled epithelium (<•/.) ; a parenchyma tracheid (frj.), and the summer wood (s.w.). X 300 RESIN PASSAGES 133 row. or m the third if present, they become narrow and very long, and they eventually blend with the parenchyma tracheids through intermediate forms with bordered pits. All of the epithe- lial cells are thick-walled and strongly pitted, and they thus offer a somewhat strong contrast to the rather thin-walled parenchyma tracheids with bordered pits. The resin passages of Picea differ from those of Pseudotsuga and Larix in being more strictly segregated, and in consequence there is a con- spicuous absence of contig- uous structures, which may nevertheless sometimes be P^^'. seen in P. nigra, and espe- cially of coalescent forms. They are usually narrow, but well rounded or oval, and there is far greater uni- formity of structure and form than in any of the pre- ceding types. The epithe- lium consists of one row, one to two rows, or even one to three rows of cells, — differences which appar- ently belong to particular species, though no attempt has been made to define the precise limitations of such features. The cells are generally small, round, or radially flattened and thick-walled, though occasionally a cell may be 'hm-walled, as in P. alba. In cases of thick-walled epithelium the outermost cells merge with similar tracheids, from which they are not readily distinguishable, while the general epithelium becomes extended into a tangentially elongated tract, as in Pseu- Uotsuga Douglasii and Pinus. Occasionally thyloses have been Fig. 43. Picea alba. Transverse section of a resin passage from the spring « ood show- ing the central canal (c); the thick-walled epithelium (ep.), and the parenchyma tra- cheids (pr.t.). X 300 i &-• *]■ iv. »34 ANATOMY OF THE GYMNOSPERMS noted in P. nigra, P. pungcns, and P. sitchensis, but they are always thin-walled. Parenchyma tracheids are not obvious in the summer wood, but they are recognizable in the spring wood, where they appear to replace the resin cells, though they are apparently of much less frequent occurrence than in the genera previously discussed. In P. alba, however (fig. 43, prJ.), we sometimes find a radial series of tracheids which also extends laterally so as to form an inclosing layer. Longitudinally the canal is continuous, but with more or less frequent constrictions, as in Pseudotsuga and Larix. The epithelium consists of narrow cylindrical and much-pitted cells, which increase in length in the outer layers, where they become five to seven times longer than broad, and finally merge with the parenchyma tracheids, which replace them. While the general composition of the resin passage in Pseu- dotsuga, Larix, and Picea is the same as that of the resin cyst, it is obvious that the frequent constrictions in the canal indicate a partial survival of the cystic formation. We must, therefore, regard these structures and the three genera to which they belong as forming a transition group between the primitive resin cyst, on the one hand, and the perfectly organized resin passage of Pinus, with its canal of uniform width, on the other. In the genus Pinus the resin passages show considerable vari- ation in detail, but they all conform to the same structural tyj^e (fig. 44). The central canal is broad and round, often very large, and in longitudinal section it is a perfectly continuous passage of uniform width. The epithelium consists of large but very vari- able and thin-walled cells in from one to several rows. In the soft pines it generally forms a concentric zone of uniform width, but in several of the hard pines there is a marked tendency to exten- sion in a tangential direction and the formation of rather exten- sive eccentric tracts. In all of the pines there is a pronounced tendency for the epithelial elements to become so thin-walled that they are readily broken out in making sections, while in the hard pines, as P. cubensis, P. tneda, P. pungens, etc., the cells are often strongly resinous. In the outer epithelium the RESIN PASSAGES H •oj thm-walled elements may be associated with occasional thick walled elements with which th , are interchangeable, precisely as m the similar relations displayed by the medullary rays of P. pungens and P. cubensis. In the same region also there is a simdar association with and transformation into parenchyma tracheids. which also has its parallel in the medullary ray. Some- wliat more specifically, special reference to two examples may S.W- SM 'iL.IfZ «^^'«-^A Transverse section of a resin passage from the inner re inc e„rr^ wood showmg the central canal (C); the thin-walled and rsr»-»and .h ^'■^■'' "'^P-^^^hyma tracheids (/.); the spring wood (.">/.«.) and the summer wood (S.ll\) x 225 serve to illustrate the general nature of some of the more im- portant variations. In longitudinal section the parenchyma tra- cheids are usually of much greater length than the associated parenchyma cells, with which they are parallel or conterminous, and they occur in large numbers in P. Lambertiana. In P. reflexa they are conterminous with parenchyma cells, which they finally succeed, to be replaced in turn by thin-walled wood ttacheids. In P. Lambertiana they are always to be distinguished by the K^ 136 ANATOMY OF THE GYMNOSPERMS : i* V;J ' bordered pits on the radial, tangential, and terminal walls, while in P. reflexa they are characterized by the large number of bor- dered pits on the radial walls, with very few on the tangential walls. In the former situation the pits are much smaller than in adjacent wood tracheids. Together with adjacent wood tra- cheids the parenchyma tracheids may be more or less involved in bearing resin (P. Lambertiana), while finally, as exhibited in transverse section, their numbers may be so large that they form extensive areas about the resin passage (fig. 44). In such a case the sequence of elements in transverse section would be : 1. Canal with thyloses. 2. Thin-walled epithelium. 3. Epithelium and cylindrical parenchyma tracheids. 4. Parenchyma tracheids. 5. Wood tracheids with thin walls. Thyloses are a constant feature in the structure of the resin passages of Pinus (fig. 31, a). They are always thin-walled and completely fill the canal. So constant are these features in association with those previously recounted that they serve to afford a ready means of accurately recognizing the genus under all circumstances. The general course of development thus outlined shows that the parenchyma tracheid stands in such relation to the organiza- tion of the resin passage that its more frequent occurrence is directly correlated with a higher type of organization and devel- opment in the plants to which they belong. We are now in a position to present a general summary of the relations which the resin cells bear to the organization of the secretory reservoirs — csts and passages — and the position which the latter occupy in the economy of the plant as follows : 1. Resin cells, which are of the nature of wood parenchyma, at first occur as isolated structures filled with resin, but they show a definite tendency to association and later form definite aggregates. 2. Parenchyma tracheids become associated with such aggregates for the purpose of effecting a more complete nutrition of the secretory cells. RESIN Passages ^37 central canals of indeterminate length °""'^ '*'''' °'" a. the tracheids. which provide nutrition for the secret ceirs "rSTeTpS."^ '"^'^"^ '" *^'- *^^ --"'of the " ''^?:r;L:^::;r' ''^^''^^ ^" ^-'^^^ °^ -^-^^ — ^ - -/. the thyloses, which may impede the proper storage of the resin or wh.ch may individually serve the purpose of storage ' in te7S^ "" I^' ^°'''"'''°" °^ '■^^•" '^ "°^ «^«««ive it is stored m the cells where produced. This is true of all isolated reS cells as well as of many which enter into the composition ^ complex cysts and passages. When the resin is excessTv ho^ form of ,'"'. '' ''''■'^^' '"^-^ ^P^^'^"^^^ r^e-oirs c^f the form of closed cysts or of canals, and we are led to interpret the appearance of these structures in the higher Conif rL aTl v.il thus be seen to stand in direct relation to the capacTv of the plant as a resin producer, -a fact which is otherZ al/ ent from our knowledge of the general capacity of the diSm SthTi r" '"'"""' ^"' '^""^ ^ ^-P--" of this ! with theu: known position in the line of descent. CHAPTER X RESIN PASSAGES {continued) Distribution and Phylogenv Prantl (62, 37) states that resin passages occur in the wood of "most Abietineae, namely, Pseudotsuga, Picea, Larix, Pinus, and Abies firma." This statement requires some modification in detail, especially with respect to the last-named genus, and in order to make the results of the present studies clear it will be expedient to discuss separately the distribution of the resin cysts and the resin passages. The first species to which our attention may be directed is Tsuga Mertensiana. This is the only species of the genus in which definite resin cysts are to be found. Such structures arc never numerous, and they take the form of short rows of con- tiguous cysts in the initial layer of the summer wood of distant growth rings. Longitudinally they have no definite limits, but they appear to be extended for great distances, and probably through the entire longitudinal growth of the season, at least. There is no obvious alteration either in the position or volume of the resinous contents of the isolated resin cells which lie on the outer face of the summer wood. The constancy with which these structures occur gives to them a definite value for the recognition of the species, and permits us to differentiate it from T. caroliniana on the one hand, and from the remaininj,' three species on the other. In the genus Abies only four species out of eleven show- resin cysts. These are A. bracteata, A. nobilis, A. concolor, and A. firma. Referring again to Prantl's observation (62, 37), it must be pointed out that his statement with respect to the occurrence of resin passages in A. firma requires modification in ■38 RESIN PASSAGES '39 detail m so far as these structures are not passages but cysts ; wh.le he al8o appears to have overlooked the occurrence of simi- kr structures m the three other species mentioned. In all of these cases the cysts are contiguous and disposed in tangential rows of considerable length, either in the summer wood (A con- co^r and A. nobilis). in the outer spring wood (A. firma);or in both the spnng and summer wood (A. bracteata). Such varia- .ons appear to be of no specific value, conforming as they do to similar varmtions in the zonate distribution of the rem cells Lir^' ^"""^'^''J^^' •" «"ly one case (A. concolor) are these cysts associated with isolated resin cells. In the three '^^ '': "^'" ""^ "^ '""'''^'y -"ting.-a relation uhich IS strongly suggestive of their replacement by the cysts Sequoia sempervirens is the only species of that genus which develops resm cysts in the secondary wood, though Jeffrey (24) has shown that such structures are normal to the primary wood^ zone of S. gigantca. and not elsewhere. As already shown, such cysts are much more highly organized than those of either Tsuga or Ab.es. though they are similarly contiguous and even ccS cscent, and form ext-rnsive tangential rows in the initial layer of the spring wood of d. .ant growth rings. They form a much more promment feature than in any of the preceding species because of their generally larger size and the greater extent of the serie! ■n which they lie. Unlike Abies, however, there appears to be no cl.minut.on either m the number or the extent of The prominent resm cells, wh.ch are often intimately associated with the cysts The normal course of development for such cysts as are thus This is the less remarkable, how- ever, because 'It species is undoubtedly the ancestral form of, and practical!' lentical with, S. sempervirens. The fact made clear by ', .11.^ a4, 457) that resin cysts occur in the first annual ri: _ -u ^i, orous branches of adult trees, as well as in H ntea, also tends to make it apparent that the a very striking advance upon even the type T Tus, since the aggregation of resin cells and • . , *" '• T jm has arisen abruptly, and with- ... pjcsented by Juniperu-. and Taxodium. . '<>ia IS obviously related to Thuya and K hand, it is, on the other hand, related to in this sense it may be regarded as the terminal member of .1 ilovelopmental series embracing the Taxo- diinae, Cupressineac, Taxoideae, as follows : the root- genus p i:.i;:ii a exhibited hy '\ :y the fonr u <. ■ c , out the tr.itisilionn While, th. • .f.w Cupressus. on thi such tyiK's as A\<1 1. Taxus and Torreya. 2. Thujopsi.s. 3. Crj'ptomeria. 4. Podocarpus. 5. Cupressus. 6. Thuya. 7. Libocedrus. 8. Taxodium. 9. Juniperus. 10. Sequoia. In the Abietineie a new .series is presented. This is not in any sense strictly conterminous with the first, but the two appear to make a fault, as it were, whereby there is a lateral disphco- ment, but of such a nature that Sequoia still serves as the con- necting link. Within the eleven species of Abies investigate three important phases are presented, — (i) resin cells scattering on the outer face of the summer wood, (2) resin cells j,Toupe(i and forming cysts, and (3) resin cells entirely wanting. Viewini; these phases in the order given, it is to be observed that in those ' While Jeffrey has shown (t») that in S. Penhallowii the resin clU are nor mally confined to the outer face of the summer wood. * This latter relation has been recently emphasized by Jeffrey (SS) througi. studies relating to S Penhallowii, and it is in direct confirmation of conclusions already reached by Her.hallow (44) on the basis of other data. RtSlN PASSAGES M5 four tpeciM which develop cysts only one »how« isolated resin cells, and it is probably correct to interpret the variation! notcnl a» exprestions of developmental phases in such a way that the occurrence of cysts represents the highest position. The genus Tsuga IS closely related to Abies in the occurrence of isolated rcsm cell! on the outer face of the summer wood, as also in the formation of resin cysts, but it obvi<,usly occupies an inferior position because (i) of the greater abundance of resin in the individual cells, and (2) the occurrence of definite aggregates of resm cells without the formation of cysts. This series is directly extended by those genera in which definite resin passages re- place the simple cysts, since the latter are convertible into the ormer by easy and natural transitions. Both Pseudotsuga and I-irix occupy equivalent positions because they not only present resui passages of an equal degree of development, but t„oy also show a survival of the isolated csin cells on the outer *irc of the summer wood. Their a«fin.tment is •named, and it therefore terminates the series upwardl). Having special reference to the particul. forms of the secre- tory reservoirs, and leaving out of account all thcr consi. a- tions than their particular evolution, it is poss ',le to indi te the general sequence of the Renera, and, to a m e lit ed extent, of their specie- as foll-.ws : I. Tsuga caro- liniana. TsuKa Mer- tensian.i. 2. Abies bracteata. Abies firma. Abies noi)iIi.s. Abies conrnlor. From this it is manifest that Sequ- Abies, but inferior to Pseudotsu'ra. ; Sequ a. 4 Pseu»;ot.suga and Larix. 5 !'ia 6. I'int -. is npcrior to Tsuga and rix. <. c. Hut if we now — 0-- • •"> ^ '• "v'l II wc now View the general phylogeny with reference u ihc entire course I 146 ANATOMY OF THE GYMNOSPERMS of development of the resin cells and the resin passages, the rela- tions just explained must be modified with reference to the partic- ular position of Sequoia, and the sequence would then become : 1. Thujopsis and 5. Libocedrus. 10. Abies. Cryptomeria. 6. Taxodium. 1 1 . Pseudotsuga and 2. Podocarpus. 7. Juniperus. Larix. 3. Cupressus. 8. Sequoia. 12. Picea. 4. Thuya. 9. Tsuga. 13. Pinus. But it may assist in the general argument to view this ques- tion from another standpoint. Regarding the resin cells and the secretory reservoirs as falling within a definite series, we may apply to the various forms of distribution, and to the various grades of resin reservoirs, arbitrary values of such a nature as to represent our conception of their relative positions in the scale of development as expressed by percentages, thus : Resin cells scattering 25.0% Resin cells zonate 37. j •Resin cells grouped 50.0 Resin cells on the outer face of the summer wood, as in Pseudotsuga and Larix 12.5 Resin cells on the outer face of the summer wood, as in Abies (partial only) 5.0 Resin cells wholly wanting 0.0 t Resin cysts, as in Tsuga, Abies, and Sequoia 70.0 Resin passages with constrictions, as in Pseudotsuga, Larix, and Picea 80.0 Resin passages without constrictions and of the highest type of organization, as in Pinus loo.o We obviously have two subordinate series here, which for convenience may be regarded as conterminous, but which, as already shown, are " faulted " in such a way that the grouped resin cells (•) and the resin cysts (f) jointly represent the point of divergence for two separate courses of development, the latter continuing upward, while the former descend and thereby represent degradation. These features are best exhibited graph- ically, and the accompanying curves clearly show how, on the one hand, resin cysts and resin passages directly result from lOOl ifl Fig. 45. Curve showing the approximate development of resin passages and the corresponding obliteration of resin cells ^ M7 148 ANATOMY OF THE GYMNOSPERMS Hit- special modification of cell aggregates, while, on the other hand, from the same starting point, there arises a course of degrada- tion which finally results in the complete obliteration of the resin cell as an independent structure. The facts thus far set forth have thrown important light upon the general course of development of certain anatomical features, and they also show the general course of development for genera and species with reference to particular structures. They do not, however, convey any information with respect to the origin of the phylum as a whole, or the relations of the particular genera and species from the standpoint of collective data, and such a discussion will be more appropriately reserved for the general summary. 1 ..ere is, however, one feature arising out of recent investigations which calls for consideration at this point, since certain of the conclusions reached are not in harmony with our own, the divergence of opinion indicated being the result of different methods of interpretation. Jeffrey states (24, 447, 457) that all such resin cysts as occur in Sequoia sempervirens and Abies are of a traumatic nature, and therefore pathological. To this categc/y he would also doubtless assign the corresponding structures of Tsuga. This opinion appears to be shared by Anderson (1, 2), and it is also ipparently supported by Pierce (60). Both Jeffrey and Anderson show that the development of such cysts is sometimes definitely associated with the production of tumors through the operation of parasites, and that they may also be induced by wounds experimentally produced. The facts they cite show con- clusively that resin cysts may and often do arise traumatically, and such is unquestionably true of Sequoia Penhallowii, as shown by Jeffrey (25) within the Units of our present knowledge of that species, but in such cases they lie outside the usual course of development. The occurrence of resin passages in the fundamental tissue of the Coniferales is a well-known fact, as pointed out by De Bary (13, 44') many years since, when he summarized the general facts in the statement that "all investigated species of Conifeia , RESIN PASSAGES 149 n reservoirs, wh.ch ^^ry m distribution and number according to the spec.es. This statement would include the leaves and bark and sometimes even the pith of species which produce nather isolated resin cells nor resin reservoirs of any kind m he xylem tissue of the stem. It directs attention somewha" orciWy to the fact that while the occurrence of resin reservoir m the fundamental tissue is a legitimate inheritance of the mucilage canals of the Eusporangiate ferns and the Cycado- fihces. as also later of the resin cells of Cordaitales. the xylem structure is the very last to receive the impress of such a cours" of development; and it is therefore in nowise surprising that the resin passages do not appear there until a very late period of development, and that their organization can even then be brought about only through a somewhat prolonged series of changes which are initiated by the occurrence of isolated resin cells, much as the formation of mucilage canals may be traced back to specialized cells which separately have the same func- tion in the Eusporangiate ferns. The local occurrence of resin passages in the xylem of the Horal axis m no way invalidates the obvious conclusions to be drawn from these statements, since it may be readily accounted for in other ways. In a structure so unresponsive to influences which would induce profound alterations as the xylem. it is to be expected that important structural changes could be effected only after a prolonged interval during which the fixation of any particular character would be preceded by a period of sporadic development, within which such character would be liable to recur under special conditions; and as such conditions are obvi- ously of fundamental importance, we may inquire somewhat more fully into their nature and results The statement of Prantl (62. 35). that "Those genera which are devoid of resin passages in the wood of young and vigorous groNvth later produce single parenchyma elements in the wood which contain resin." requires some modification in view of what Jeffrey has shown in the case of Sequoia and Abies, as well as ifei >50 ANATOMY OF THE GYMNOSPKRMS what has been shown in the course of the present studies, and in its more comprehensive and exact form it should read, " Those genera which are usually devoid of resin passages in the wood, but some species of which may nevertheless contain resin cysts in the young and vigorous growth, later produce single paren- chyma elements in the wood which contain resin." Taken by itself, this statement as applied to Sequoia and Abies might be held to indicate that the growth of the first year represents the most stable structural region of the entire stem, in the sense that it embodies characters which are most fully established, and that it will therefore embrace elements which may be eliminated from the older parts, or which may be replaced there by degenerate forms only. From this point of view it would be necessary to regard the complex resin passage as the primitive form of structure from which the cysts, groups of cells, and isolated lesin cells have been derived by a process of progressive degradation. This view appears to have been adopted by Jeffrey (24, 454), who supports his position by citing the occurrence of resin passages in the va cular structure of the peduncle of certain fossil Cycads, interpreting this to mean that such structures represent a survival of features which have been obliterated from the structure of the stem. Such a view does not seem to be in harmony with the facts which our own studies have brought out, to the effect that resin passages of the type found in the xylem structure are in no sense primitive or vestigial, since they are wholly wanting in the primitive gyni- nosperms, and their organization does not arise until a very late period in the evolution of the higher forms. If our interpretation of observed facts is correct, as applied to the origin of the resin passages, it shows as clearly as one could well expect a pro- gressive development from the isolated resin cell through vaiious phases of aggregation to the highest form of structure as found in Pinus. That there is such a series cannot be doubted, and we must interpret it in one of two ways, — either as progressive evolution or as progressive degeneration. To us the arguments all seem to be very emphatic with respect to lending support to RESIN PASSAGES .'he re,:::: zizTorr"'" ^ -" """""■"' •^•^ ™«™ .ta .he ,a„er vj?, ^Z.Z:Z::V"' ^'^ "°"''"' >-• u. u „„„,4 fi„. „t „,, „,c'e™:;,"a *« ;t'L;; re .hat such a prop„si;io„ w„„U ml. ^rmlr'"" '° "«^"' tutes the most impressionable portions of the «;f^m J 7 higher pu„.s, bu. .hey are Zo 1 y , rTrsT; 0?°"*,."° 2. Resin passages are wholly unknown in the wood of fh. a^if ihe 'l:^r":V", ° ""-^ ■" "^ '^'■"*» °' Se<,„„ia se,.«aptr!?:rs:-:n:;t^^^^^^^ 5. In Sequoia Burgessii, from the E,-ccne resin n.T^' ill 152 ANATOMY OF THE GYMNOSPERMS From this it would seem that the fundamental tissue is the most impressionable with respect to the development of these structures, and that after it we have in the same order the peduncle of the inflorescences and the wood of the young shoots, to which latter category would also belong the development of resin passages in fasciated stems, and such a sequence is pre- cisely what we should expect from our knowledge of the relation which the fundamental tissue bears to other structures. Accord- ing to this conception the resin passages may appear in any part of the woody structure where growth is sufficiently vigorous, but such appearance would be temporary and indicative only of a future course of development which has not as yet become sufficiently well impressed upon the organism to form a perma- nent feature of it. In other words, the tissue exhibits what in other cases would be termed "sports." Such structural fore- casts are well known and of frequent occurrence. As applied to the development of tissues, no better example is afforded than that shown by the central strand of mosses, which is generally accepted as prophetic of the future vascular system in the spo- rophyte, and they serve to suggest that the law of mutation as proposed by De Vries finds expression in the evolution of internal structures as well as in the development of external forms. Such cases as Sequoia gigantea, which shows resin cysts in the wood of the first year and nowhere else, being replaced later by resin cells, appear to us to show that young and vigorous growth in general, and therefore the growth ring of the first year, consti- tutes a transitional zone within which many changes of structure wholly apart from the strictly normal may arise; and such a law would similarly be applicable to the wood of peduncles. This feature is manifested in the structure of the medullary ray, the character of the tracheids as exhibited in transverse section, the genesis of the bordered pits from spiral tracheids, and, in all probability, also in the formation of resin passages in Sequoia and Abies, as noted by Jeffrey. Changes of this nature are to be regarded as tendencies in development in the direction of higher types of structure, whereby RESIN PASSAGES potentialities assume a more or less definite for™ p may be assumed that the primarrRrowth rinJT" '*"' '' The considerations dealt with here as wpH oc • Chapters, lead us to give renewed TrnpLr / :L^^r: has been expressed elsewhere, and which finds justiic^tiL t many v^ys no, ,„,y j„ ^,^ gymnosperms but in the sTl "^ and m Catalpa among the angiospems. to the effe.! fh primary .mportance. and such changes are no dou^etbl^h^ external morphology in questions of classificatioa CHAPTER XI GENERAL PHYLOGENY The results to which we are now brought are based entirely upon developmental phases in anatomical elements of the vas- cular cylinder. While our studies lead to certain definite con- clusions, we do not in any sense regard these as final, but only as affording one step in the solution of a question which must be viewed not only from the broader standpoint of more extended anatomical data but also from that of physiology as well, although we feel disposed to insist that the final answer will be found to rest chiefly upon an anatomical basis. That there may be room for a different interpretation of the facts here recorded is quite possible, since Dr. Jeffrey has recently permitted me to exam- ine the manuscript of an important contribution to our knowl- edge of the Abiecineae, in which he brings out very significant facts, which suggest that the group is of a much more primitive character than has hitherto been supposed or than is indicated by our own studies. It is therefore of importance that final judgment should be suspended until the results of these various studies, as well as those of Coulter, Chamberlain, and Ferguson, all directed to the same end but prosecuted along somewhat different lines, can be brought together and coordinated. It is in this sense that the following conclusions are offered. In discussing the phylogeny of the higher gymnosperms three subordinate phyla must be taken into consideration in the following order: (i) Cordaitales, (2) Gingkoales, (3) Coniferales. Regarding the Cordaitales a" the most primitive gymnosper- mous stock of which we have present knowledge, it is possible to trace its origin to the Cycadofilices. The genera Lyginodendron, Heterangium, and Calamopitys present many structu; . 'eatures which are common to all, and which not only cstabl^^h their '54 i "1 GENERAL PHYLOGENY ,-- relation to the Cycadean line of descent but also offer many suggestions of that course of development which is realized in the higher Conifen^les. They therefore constitute the re ^art" he Cycadales At the present moment we have little or nothin. to do with th,s beyond establishing its probable relation to hf other gymnosperms. The second line emerges in a type of plant^ having charactensfcs distinctly allied to those of the Coil and U IS this line of descent with which we are now chiefly coni cerned^ t ,s now possible to define the origin of this phylum somewhat more exactly than Coulter has done (11. W) ^nc^ there •« good reason to believe that it emerges from the Cycad^^^^^^ that the two were m any sense conterminous, and it is altogether 156 ANATOMV OF THE GYMNOSPERMS probable that there may have been some one or more intermediate forms of which we have no present knowledge. Our present studies, on the other hand, show clearly that we must bring into this phylum two other genera of an obviously higher degree of development, but which have commonly been ranked with the Abietinex and which, according to Eichler (15), occupy the highest position in the scale. This position is untenable upon anatomical grounds which give us reason to believe that Dam- mara and Araucaria (including, of course, Araucarioxylon) are not only inferior to the Coniferales as a whole but that they are also distinctly Cordaitean. Accepting this view and the fact that Dammara is the inferior genus, the sequence would place Cordaites at the base and Araucaria at the top, with Walchia as the immediately ancestral form of the latter. This relation is not only natural but it is justified on anatomical grounds. The tendency to segregation of the bordered pits, as exhibited by Poroxylon, suggests the relation of this genus to others in which such a feature is fully expressed, and it thereby forms the basal member of another series. From the opposite point of \iew it has been shown that the occurrence of two-seriate pits in Pinus and others of the Coniferales, as well as in Gingko, points to a com- mon origin for such genera in a type with multiseriate hexagonal pits, and that both Dammara and Araucaria must likewise center in the same generalized form. This gradual convergence is justi- fied on other grounds, and the genus Poroxylon among known forms most nearly fulfils the requirement* of the case. We may therefore look upon it as lying between the Cycadofilices and all the higher gymnosperms, giving rise to two lines of descent, the first of which embraces the Cordaitales, as already described, while the second shortly divides once more. This secondary division gives rise on the one side to the Gingkoales, and on the other to the Coniferales. The anatomical data already discussed, when viewed collectively, show that the general sequence within the lat- ter would be (I) theTaxoideae, (2) the Taxodiinx, (3) the Cupres- sineae, (4) Abies, (5) Tsuga, (6) Pseudotsuga, (7) Larix, (8) Picea, and (9) Pinus, of which one division, (II), represents the highest GENERAL PHYLOGENV ,-- type of development With respect to the precise position of Seqaou .„ particular, us relation to Abies on the one^aTand ntor t '' ' ''"'" °' our knowledge, to indicate it, origin from or .ts ancestry to either of them. The facts derived frfm anatomy, however, do indicate a more or less common ori^n fo aH ^ur genera, and from this point of view, taking into account th" pecuhar futures exhibited by Sequoia, they would seem to justify the .dea that that genus represents a short side line of deveW ment ^vh.ch does not lead to the evolution of other typeTbu^ tcrmmatesm S. gigantea after a comparatively brief per^Thl sequence of species for each genus cannot al^ys beTe^rmilL 2t yi TT '^ ^^"f^«'°". ^d these difficulties may Z •bly be nude clear by reference to the succession of the Z. pec.es of Sequoia, which is difficult to determine on purely ana om.cal grounds, but the general tendency of the facts a^ ected « o give to S. sempervirens the more primitiveTosf "'h7reir t^' 'r"^'^'""' 'y '^^ Paleontol^gi™! ; St'; reaLns orT CO T ' "' " ^'^ '°"^°'"^ ''-^'^' -^ t7e w'thou ^°V^;;°-^^'"^'«"« >-^-hed. may be made more obvious, without the tedious method of a detailed discussion, by refer ence to the accompanying table of anatomical data (AppZ^Z wh.ch substantially summarizes all the results deriveTf rom fht study of particular structures. In preparing this table the vTriouI anaom.cal features have been chosen with reference to "h and (3) their obvious relation to diagnostic purposes. In thei^ horizontal extension an attempt has been maLrarrange 4em n accordance with the law of frequency, as well as with ^fferen" o he re,^,,^„ to development, in such wise that while the s^! mlvK K u ^'"'"" °^ '*° ^•"''^ °^ «"» '" the medullary ray may be held to express the highest form of development To while those subordinate characters which are represented by I ■58 ANVTOMY OF THE GYMNOSPERMS different forms of di»tributbn may be regarded as forming a second series similarly valued. Any primitive or other character which has become obliterated through development may be held to retain its original value with respect to the general course of such development, and it it always indicated by -. Vestigial structures occurring sporadically ane designated by i, and to them one half the value of the fully devel«»ped character is assigned. All normal features are designated by x, which becomes x + when they show deveJopment toward the next higher form, or x - when they show a definite tendency to degen- eration. Sporadic characters which are obviously in the line of development are indicated by o, but they are assigned only half values. On this basis it is possible to arrange a sequence of genera and species in such a manner as to exhibit a progressive development from the simple Dammara, with a minimum of char- acteristics, to the complex Pinus, in which the greatest number of anatomical features is involved. Furthermore through such a series it is possible to determine the relative position of the vari- ous genera by percentage values, and it gives the most valuable insight into the approximate relations of the various members within the general line of descent. Such relations are determined not only for each anatomical character but also for the collective characters. Reducing these facts to a graphic form, the accom- panying curves wUl assist in making the relations more clear, especially in emphasizing the general course of development, and, in their final form, they are best expressed by a biological tree. A figure of this sort is diflScult to construct, and there is no agree- ment among investigators as to the p; ticular form it should take. While the figures in common use indicate a certain relationship in descent, th ey completely fail to convey any impression of the way in which the succession arises, and they furnish no indica- tion of possible gaps. They therefore constitute a very poor working basis. In teaching I have long been accustomed to compare the various lines of descent among plants with the branchings of a deliquescent tree, since it has always seemed reasonable to GENERAL PH LOCJENV >59 suppoM that the laws which «•'" n the- I. mching of a hmb which give rise to a!I the varying i.,rms of a. .ted tlevelopmcnti and which thereby determine a p^ulicular modification of the hgure which would otherwise result from unmodifieri g,.wlh. must be equally applicable to the general evolution of the hi^'her forms of plants from a common juicestral type. In endeavor- ing to secure a nai jral growth which would best exprcs* all the lOO' ' ■! 3 4 S 6 7 8 9 lo II 12 1 5 I t l.S l6 17 l8 19 ;o Ji 22 23 J4 25 211 Fu. 46 Carves for sequence of genera and frwjuency of anatomical characters of the Cordaitales. Gingkoules. a..d Coniferales : ./. sequence of genera- ff, specific characters; C, generic character-^ conditions in\ olved, the branching system of the Norway maple (Acer platanoides) seems best suited to an illustration of all these Iihasesof terminal growth, suppression, and relations of successive members which we conceive to be re[)rescnted in the development of plant phyla, inasmuch as it conveys the idea of succession through lateral members in such a way as to indicate the chief hne f de .ent. The branch of the Norwav maple, when of vigor- ous fero*th, is a monopodium, and tt is oh\)ous that such would i6o ANATOMY OF THE GYMNOSPERMS not answer the object in view, since its most prominent feature would suggest the idea of a continuous series of conterminous members, from which lateral members would arise at intervals. There is no evidence that any phylum represents such a series ; on the contrary, there is every reason to believe that such relations do not exist among the various groups of plants. In those branches of the Norway maple which exhibit slow growth various forms of arrested development are manifested. These take the form of atrophied buds, or of branches in all stages of development, and there thus arises a modified monopo- dium which eventually becomes, in many cases at lerst, a true sympodium. In comparing this with the monopodial branch of vigorous growth, it appears that the alterations involve more than mere suppression. In the monopodium the average angle of divergence for the lateral members is 45 .3 degrees, while for the derived form it is 34.1 degrees. The latter will be seen to com- pletely fulfil all conditions with respect to the development of a phylum, even to indicating the position of missing members. In the construction of this figure an attempt has been made to show all normally developed buds (O) and their relative dimen- sions ; atrophied buds (o), the position of which is recognizable ; and atrophied branches (Y) which are still visible, but it is obvious that the figure does not show many members all evidence of the former existence of which has completely disappeared. Selecting from this we obtain the accompanying figure, which embodies our final conclusions as to the general succession of the different gyronosperms, and from it we may gather that the highest repre- sentative, Pinus, is the terminal member in the main line of descent from the Cycadofilices through Poroxylon, while from s'-h a central line both the Cordaitales and Gingkoales have been given off as side lines. The general results of these investigations serve to confirm in a very striking manner the probable monophyletic origin of the gymnosperms, as already expressed by Coulter (11), while they also show that the real transition ground, at least for all but the Cycadaceae, was probably represented by Poroxylon, as indicated by Scott (81). <*f \ I g I 11^ it t 9 t6i F '^''^ ' CHAPTER XII DURABILITY OF WOODS AND THEIR PRESERVATION AS FOSSILS One of the most important questions which enters into the consideration of those who are called upon to employ timbers for the various constructive purpooco to which t^ey are adapted, is their ability to resist decay in its various forms, or their dura- bility. Different species of woods vary widely in this respect, as may be readily ascertained by consulting the data collected by Professor C. S. Sargent in his Tenth Census Report upon the Forest Resources of the United States, and as appears in the sec- ond part of the present work. In general terms it is probably true that the more resinous woods are more durable than those which are less resinous, this being the direct result of the preservative action of the resinous material, which is in itself highly resistant to decay, and which further acts through its somewhat well- defined antiseptic properties and therefore behaves toward the general structure as a natural preservative, while it also excludes water from the interior parts and thus tends to limit the opera- tions of fungi. Thus it may be stated broadly that the resinous conifers as a whole are more durable than the nonresinous woods of the higher angiosperms. Or among the conifers them- selves the hard pines are more durable than the soft pines, as may be seen by a comparison of the southern pine (Pinus palus- tris) with the white pine (Pinus strobus). But apart from the presence of resin, which may be localized or disfibuted through out the entire cellulose skeleton, it is altogether probable that the durability depends to a very large extent upon inherent projier- ties of the cell membranes which have become variously modifiod in the course of growth and thus adapted to this end. Thus it has already appeared (Chapter III, p. 48) that while the unmodified 162 DURABILITY OF WOODS 163 cellulose contains approximately 44 per cent of carbon, the lig- nified tissues contain upwards of 68 per cent of this element From this we are led to conclude that tissues yield to or resist decay just in proportion to the extent of such modifications, which are to be regarded as of a protective character. If this principle be extended to lignified tissues in general, we must then admit that smce the extent and quality of the lignification do not develop equally in all species, these latter must exhibit corre- sponding differences with respect to their ability to resist the dismtegration attending what is commonly called decay, whether such decay arises primarily as a process of slow oxidation or whether it is initiated through the operation of active enzymes The general law thus stated has an illustration in a very striking instance of the relation which the special character of the cell wall bears to agents promotive of decay, as recorded by von Schrenk (68, 49), who shows that while Polyporus versicolor readily attacks the living catalpa tree and produces widespread decay, there is no fungus which will attack the timber when once It has been cut and seasoned. — a fact which serves to explain the astonishing durability of this wood in spite of its great porosity. Another factor of great importance is to be found in the con- ditions which immediately surround a given timber, since it is a well-known fact that the same species of wood does not exhibit the same degree of durability under all conditions. Thus wood in a well-drained and well-aerated soil will have a much longer term of life than it would in a wet and badly aerated soil Or again, the same difference would hold true as between a com- paratively sterile soil and one which is rich in organic compounds. The life of a timber in salt water is far greater than in fresh water, or even than in well-drained soil, owing to the specially preservative action of the salt ; while the durability may be mdefimtely prolonged if the wood be hermetically sealed in an impervious matrix such as clay. These differences are readily susceptible of an explanation by reference to the relation which the various media bear to the growth of fungi and bacteria, since wc recognize in these two groups of plants the active agents 1 64 ANATOMY OF THE GYMNOSPERMS which constitute the source of decay. It is not our purpose to discuss the particular mode of action of these organisms at the present moment, since that is more appropriately reserved for a subsequent chapter, but a few concrete examples will serve to indicate somewhat more exactly the relative durability of certain species under widely different conditions. One of the most instructive examples to which our attention has been drawn, not only because of the very perfect state of preservation but also because of the great length of time the wood has resisted the action of decay, is to be found in Sequoia Penhallowii, as recorded by Jeffrey (25). The wood in question, representing a large fragment of a tree at least six feet in diameter, presents the external aspects of a recently cut piece taken from an existing tree. It is of Miocene age, and was obtained from the Sierra Nevada Mountains on the line of the Central Pacific Railway, under sixty feet of conglomerate, where it was located in the auriferous gravels. No difficulty was ex- perienced in making sections of this wood for the microscope, no more than would be encountered in wood taken from an exist- ing tree, since it was very slightly silicified. A microscopic examination shows the structure to be most beautifully and per- fectly preserved in all its details ; while several beautifully pre- pared sections, for which I am indebted to the courtesy of Dr. Jeffrey, also make it evident, from the complete absence of fungus mycelia, that these latter had not found their way into the tissues at any time during the long burial of the tree. The special interest of this wood centers in the fact that, so far as I am aware, there is no other example of an uninfiltrated and unaltered wood from so ancient a formation. More recent Tertiary strata afford numerous examples of a similar character. The Pleistocene in particular has furnished many instances of the most perfect conditions of preservation, chiefly of woods which, under ordinary circumstances, would be regarded as " durable." In 1898 Professor A. P. Coleman of To- ronto obtained from the Pleistocene chys of the Don valley, at that place, a specimen of the common red cedar (Juniperus virginiana) UURABIMIY OF WOODS »65 which exhibited all the external features of that species, includ- ing the char?cteristic color and fibrous bark (48, 562). When cut with a saw the well-known odor was given off somewhat freely. Under the microscope the structure was found to exhibit no evidence of alteration, while there was seen to be only a limited development of mycelial filaments, — not as much as may often be found in badly seasoned logs. This condition of preservation is to be ascribed chiefly, no doubt, to the fact that the wood was hermetically sealed in an impervious cby which completely excluded all fungi and inhibited further growth of those originally present. This explanation appears the more probable from the fact that leaves of the Vallisneria spiralis, embedded in the same clays, show all the details of the original structure when freshly exposed, and it is only upon subsequent dessication that disorganization takes place. Juniperus californica from the interglacial deposits of Hum- boldt County, California (46), offers a very similar though much more instructive example of preservation through long periods of time. This wood was obtained from two localities, in the one case occurring in blue, sandy silt under one hundred and fifty feet of local debris, while in the other case it was embedded in blue, slaty muck under fifty to sixty feet of local debris. A microscopic examination showed that the structure contains very few mycelial filaments, in fact only slightly more than in the Don specimen of Juniperus virginiana. The structure of the tissues is well preser\ed and gives no evidence of that oblitera- tion of parts which usually accompanies the operation of fungi and bacteria, whence we may correctly infer that such organisms were not operative. It was nevertheless found that the tissues did not offer the normal amount of resistance to the action of the knife in cutting sections, the result being a localized fragmenta- tion. The material was only very slightly silicified and there was no difficulty in the removal of the mineral matter, but the entire structure presented unusual thickening of the cell walls, such as would arise through the action of strong alkali. Alterations of this character are not infrequent among fossil plants, most 1 66 ANATOMY OF THE GYMNOSPERMS particularly among those which are eventually silicified, and in the present instance they serve to explain the mechanical weak- ness of the tissue, the cellulose substance of which has undergone a gradual molecular alteration consequent upon the action of an alkaline solution — possibly of a hot spring — which has been continued indefinitely. The Douglas fir is regarded as one of the most durable of woods, and it is not surprising to find instances of its perfect preservation under very adverse circumstances. Specimens of Pseudotsuga macrocarpa, from the same beds as the Californian juniper already described, exhibit the same absence of special silicification, but they differ in a much more marked development of fungus mycelia, and in a .somewhat extreme alteration through the action of free alkali, which has been carried so far that in the summer wood the cell cavities are largely obliterated, while the thinner-walled tissue of the spring wood shows definite col- lapse. Apart from this there is no evidence of the removal of parts through the action of decay, and we may conclude that the fungus present had not produced any specific effect. Yet another illustration is afforded by Pseudotsuga Douglasii from Mystic Lake at Bozeman, Montana, where it was found under eight feet of the old lake-bed deposit, which antedates a well- defined and superimposed gl cial deposit. The age of this for- mation is open to discussion, as it may represent local glaciation of recent date, while there is al.so a possibility that it may be synchronous with the continental interglacial period, since the absence of the tree from the same locality at the present day leads us to suppose that its removal occurred in the time of general glaciation, as may be inferred from other evidence (46). In its external aspects the wood presents a remarkably perfect state of preservation, exhibiting all the features of grain and other structural details, even to an exhibition of the bordered pit? which may be readily determined with a hand lens of mod- erate power. Furthermore it was wholly free from infiltrated mineral matter and was readily softened in boiling water so that sections could be cut with the greatest ease. Internally the DURABILITY OF WOODS 167 detail . showing no evdence, of decay and a remarkable freedom from fungus mycelia, from which we may conclude tha! he tree was not only buried but practically hermetically sealed up 1 ,x,ss.bly by the operation of an avalanche - beLe an oppor- tumty for the action of fungi and the operations of deca^^'. The genus Picea is a widely distributed type in the Pleistocene deports, i^rfcularly in Canada. A large amount of materL has been obtamed from the Pleistocene clays of the Don valW at Toronto and elsewhere, and it affords an excellent index o^ the durab.hty of the wood under such conditions. AH of the matenal has been found to be devoid of silicification or other mmeraluation. and it presents somewhat diversified aspects with respect to conditions of preservation. P. alba, of the S IrC oush period, although the wood is fairly well preserved ifa whole and readily admits of a determination of the species shows a grea abundance of fungus mycelia. Wherever this i^ to be found there ,s a marked alteration in the structure of the cell wall, mvolvmg a breaking down of the secondary layer, as usu LTIT ?T' ^•«^"'"^^--^' ^•^'•^ disintegration being ahvays most marked m those regions where the mycelium is most abundant. In this case the relation of the fungus to the changes noted is very obvious. J!^'^'^'^'' ^'■°'" '^' ^°" '^^P''^'^^ '^ •" '^^^ ^^«es so well preserred as to permit of a determination of the species with- out difficulty, while in other cases the decay has progress J so far as to render identification impossible. Fungus m^ hf a " -ys present and they clearly constitute the active agen Itr; 7 ""'^^^ ''^^'""^ "'"'"^'""^ °f preservation here ZtT r^^T """ "^''■"'•°" "^ ^J'^^'fi*-^ ^^"«^« wholly P t om the mherent qualities of durability which the wood aturally possesses. These are to be sought for in two direc- tions, either ,n local conditions of preservation, as varying permcabihty of the soil, or in the conditions of decay established Pr.ur to entombment. All of the material has been derived from M"-': i ft *9mi I'L 1 68 ANATOMY OF THE (iYMNOSPERMS a compact clay, which offers a practically air-tight matrix of essentially the same physical character in all cases. It therefore seems improbable that local variations of the inclosing material could have been so different as to give rise to the diverse aspects of decay noted, though such may have been a factor of secondary importance. The fact that under essentially the same conditions some specimens were well preserved while others were badly decayed, at once directs attention to the probable operation of antecedent causes. It is quite obvious that trees which eventu- ally become fossilized are neither of the same age when they fall nor are they in the same condition of soundness. Some may be quite sound, while others may be infested with fungi, and the living tree may therefore present the somewhat advanced progress of decay. But the fossils of the Don deposits are obviously fragments of trees which had been brought, through the agency of water, to the places where found, and it is quite clear that while some of the trees may have been speedily buried others were no doubt a long time in the water before being inclosed in the sedimentary deposits. Decay would have an opportunity for extended devel- opment under such conditions, and it would even continue for an indefinite period after entombment. On the other hand, the rapid entombment of a vigorous tree in which decay had not yet made its appearance might involve the inhibition of fungoid growth. On this hypothesis, which seems to present the prefer- able alternative, it is possible to satisfactorily account for the varied states of preservation noted, as arising under essentially uniform conditions. The common larch (Larix americana) is another wood of very widespread occurrence throughout the Pleistocene depo.sits. Two widely separated localities may be selected as afJordin- exam- ple' its preser ition. At Dahlonega, Georgia, this species has been found in the black clays, which are to be regarded as prob- ably synchronous with and equivalent to the Pleistocene deposits of more northern localities (51). The material was found to be wholly free from impregnation with mineral matter, but it exhib- ited the somewhat extreme effects of advanced decay with the DURABILITY OF WOODS 169 subsequent operation of pressure.' so that it was with some diffi- culty that sections were made which would show structure The entire structure showed abundant fungus mycelia, while the walls of the tracheids had suffered such reduction under the operation of decay that the secondary walls were largely removed with a corresponding obliteration of structural markings, and the whole fabric was reduced to a compressed and greatly modified skeleton consisting of the primary cell walls. Numerous speci- mens from the Don valley show that while some are full of fun- gus hyphae and present a correspondingly advanced state of decay others from precisely the same locality show a total absence of all fungoid growths and a completeness of structural details which leaves nothing to be desired by way of comparison with recently cut material. Here it is still more evident that the explanation applied to Picea nigra is not only applicable in this case also, but that it affords a correct insight into the reason for the various conditions of preservation of wood which, when embedded m clay, is practically imperishable. A more recent example of the larch may serve to lend emphasis to these con- clusions, and It is of particular interest because it embodies the changes which may arise in the course of practical use. In the Peter Redpath Museum of McGill College there is a specimen of an old aqueduct log which was laid down in the early days of Montreal. The old and long-forgotten pipes were uncovered in the course of excavations for a new water main on St. Paul Street. They were about one foot in diameter, with a two-inch bore. According to a communication in one of the daily papers the pipes were laid about eighty years previous, but were in use for only a short time. An examination showed that when the pipes were recovered they were practically sound, with the exception of the superficial layers, which had so far yielded to decay as to be in process of removal, and the external form had thereby suffered some alteration. A microscopic examination showed the structure to be so perfectly preserved as to admit of 'Recent studies indicate that the amount of pressure required to produce uch results need not be very great, probably less than one hundred pounds. It 170 ANATOMY OK THE GVMNOSIMRMS klentificution without any <|iiesfion, and there was Init slight evi- dence of the operation of decay, a fnct which goes far to support the hypothesis already di?»i ussed, that if the wood is sound when buritil II) a compiut and air-tiglit matrix, its decay depends essentially upon that which had been initiated before inclosure, and that otherwise there is essentially no change. Upon assuming c^^arge of the office of governor of Montreal in 1642, Maisonncuve constnaed a palisaded fort near 'he present location of the customhouse. In 1890, in the course- of excavations in that locality, the workmen uncovered hewn timbers which were held to represent a portion of the palisade of the old fort. A specimen ot one of these may now be seen in the museum of the Natural History Society of Montreal. It represents the wood ot the common red pine (Pinus resinosa). E.Nternally the wood has all the aspects of a recently cut log, a state of preservation which is amply support etl by microscopical examination, from which we learn that there is very little myce- lium present, and that the structure is as perfect as if taken from a tree of present growth, notwithstanding its probable burial for two and one-half centuries. Data of a more recent character with respect to the duration of timbers used for constructive purposes may be derived from actual experience. Thus Dudley has found that when the yellow- pine (Pinus palustris) is employed in the ground or used as tics, it very quickly decays, being destroyed by the action of Len- tinus lepideus, Fr., although the wood is very durable under conditions of comparative dryness (14). In the case of tics from the Panama railway, he also points out that they were useless in two years, while similar ties employed in the southern states lasted from four to six years, and in the middle states they lasted from five to eight years, showing very clearly the influ- ence of varying climatic conditions, particularly with respect to the relative humidity and temperature. According to the same authority, cedar ties (Cupressus thyoides) will last from eight to ten years, even when not wholly sound at the time of layin;:, while hemlock ties (Tsuga canadensis) have a life of only four DURABILITY OF WOODS ,., yiars. The relation of special conditions of moisture is further exhibited in these cases in the fact that ties which were perfectly sound on the exposed sides are very often found to be in an advanced state of decay throuKh.nit the buried parts. Mutilation IS an important factor in the introduction of decay, and Dudley has shown (U) that where spikes have been driven into the ties and where the structure has thereby suffered mechanical altera- tion, decay finds an opportunity for speedy entrance into the interior tissues, which it rapidly permeates and destroys. This relation of cause and effect is in perfect harmony with what has long been known to occur in living trees where broken or badly amputated limbs afford an opportunity for fungi to pene- trate and destroy otherwise healthy tissues. The preceding considerations have directed attention to the fact that coniferous woods may be preserved indefinitely, pro- vided they are completely excluded from fresh supplies of free oxygen and are maintained under conditions of low tempera- ture.—in other words, hermetically sealed in an impervious medium. While we are thus in a position to understand the conditions under which a very large proportion of woods are preserved as fossils in the more recent geological strata, no explanation is offered which will adequately account for the mode of preservation of the large number of plants met with m the older rocks, even as far back as the Devonian and Silurian, and it is desirable that examples of these should be passed in review. In this connection four principal forms of preservation may be noted. -(,) carbonization, (2) silicification, (3) calcification, and (4) pyritization. Carbonhadon. This form of preservation is essentially char- acteristic of plants derived from the coal measures, and it is represented by coal itself. It depends essentially upon a gradual withdrawal of the elements of water from the original cellulose ■substance, whereby a relative excess of carbon is developed. It 's a change which takes place under exclusion of air, and it is no doubt facilitated by the action of heat and possibly also of pressure. It is obvious, however, from the nature of the changes MICROCOPY MSOIUTION TIST CHART (ANSI and ISO TEST CHART No. 2) ^ APPLIED IN/MGE Inc =; 1653 East Main Stre»l r^ Rochester. New York U609 USA ^= (716) 482 - 0300 - Phone ^S (716) 2U - S989 - FoK 172 ANATOMY OF THE GYMNOSPERMS involved, that they not only proceed very slowly, but that it is possible to find plant remains which present different stages of the process, as represented by the various forms of peat, brown coal, soft coal, and anthracite. Being determined by the with- drawal of hydrogen and oxygen from the original tissues, these alterations must arise very unequally in different parts of the plant body, as determined by the character of the tissue involved and the relative percentage of carbon originally present in the cellulose substance. In the progress of such changes, gases constitute some of the most abundant and conspicuous end products. While under ordinary circumstances they may be lib- erated continuously, they may be stored under favorable condi- tions, to be liberated in great volume at a later period. Thus it has been shown, as the result of recent observations (88), that where plant remains accumulate in large quantities, sul- phureted hydrogen together with the light carbureted and phosphureted hydrogen arise. The two latter, being subject to spontaneous combustion, take fire upon coming in con- tact with the air, and, setting fire to the associated sulphureted hydrogen, an extensive conflagration may result. Phenomena of this kind on a large scale rarely come within the observation of man, but that such have been observed affords abundant ground for the belief that many foiest fires of obscure origin are to be accounted for in this way. Thus, once more comparing the per- centage composition of the principal cellulose modifications, it is found that normal cellulose contains 44 per cent of carbon, lignin _bout 62 per cent, while cork contains upwards of 74 per cent. In accordance with this principle it will be found that wood tissue becomes carbonized sooner than the softer parts of the structure, which may already have disappeared through the operation of decay, or the highly carbonaceous cork tissue of the bark may be converted into a structureless mass of carbon, while yet the less carbonaceous wood tissue is preserved in all its details. It is thus possible, in a silicified wood, to recognize and define .he general limits of the bark by the carbonized layer which oftentimes forms the outer portion of a fossil wood. j i DURABILITY OF WOODS ,73 Carbonization necessarily involves a more or less profound obliteration of structural detaUs. This is especially true in those cases in which an absence of infiltrated mineral matter has pre- vented a retention of the original structural details, and where pressure m conjunction with heat, as in hard coal, has pro- duced a secondary effect. From this point of view it is true that a highly carbonized cortex rarely presents any structural details. Lignites and some of the softer coals not infrequently present welWefined structure, but the same cannot be expected of the hard coals, in which extreme alteration has been effected In many cases, such as may be found in the Devonian and later formations, carbonization is joined to silicification or calcification and gives rise to resultant forms of preservation, which will be discussed more fully and with more propriety in the next chapter- but attention may be directed to the general fact that where carbonization operates by itself the fossil acquires an opacity which renders it very difficult to determine details, while the structure also becomes so friable as to make special methods of section cutting imperative. Silicification. Thij is by far the most common form in which the stems of plants are preserved in the older rocks. It depends upon the slow infiltration of a solution of an alkaline silicate into the tissues, whereby the entire structure eventually becomes con- verted into a mass of silica, as in the trees of the petrified for- ests of Arizona, or as may be seen in some of the larger alga; such as Nematophycus from the Devonian. According to the rate of infiltration, relatively to the operation of decay, all struc- tural details may be observed. Under ordinary circumstances, however, such a method of preservation is one of the most advantageous for the purposes of scientific study, because of the transparency of the mass and the permanent form of the material. Calcification. This form of mineralization is much less com- mon than silicification, with which it may be combined. In some cases, however, calcite constitutes the entire mass of the mfiltrated material, as in the case of Osmundites skidegatcnsis 174 ANATOMY OF THE GYMNOSPERMS from the Cretaceous of the Queen Charlotte Islands, which, as shown on a former occasion (56), contains at least 70 per cent of calcium carbonate. The general effect of this form of pres- ervation upon the structure is substantially the same as in silicification. Pyrithation. A still less common form of preservation is that which involves a replacement of the silica or calcite of the pre- vious forms by crystalline sulphide of iron. This is a feature more or less common to fossils from the older formations, which always involves a complete obliteration of structural details, though in rare cases the more general features may be seen when viewed by reflected light. Plants presenting this form of preservation are among the least val able for purposes of scientific study. CHAPTER XIII DECAY : ITS MODE OF ACTION AND EFFECTS In discussing the operation of decay in the woody tissue of a stem, it will be desirable to have reference to (i) the nature of the active agents, (2) the conditions under which they flour- ish, (3) their mode of operation, and (4) their effects upon the structure and mode of preservation. I. T/te nature of the active agents. Decay has its origin in the growth of certain plants of a low degree of organization, which, through their ability to seek food supplies either in living or dead organic bodies, produce such an unusual course of develop- ment as to effect an actual disorganization of the tissues, as expressed in decay. To understand fully the nature and mode of operation of these plants, it will be necessary to briefly pass in review their essential characteristics. 'imong the lower forms of plants we recognize two somewhat nearly related groups, which present many features in common, both with respect to their influence upon the promotion of dis- ease and decay and to their general habits of life, but which nevertheless differ very materially in their structure and the details of their life history. The first group embraces what are known as the Bacteria, — plants characterized by their unicel- lular structure, which rarely assumes a filamentous form, and by the fact that while they may and frequently do propagate through the medium of spores, they more commonly multiply by simple fission, in consequence of which they are designated the fission fungi or Schizoniycctcs. Their life history is very simple, and the incomplete cycle, which is wholly devoid of a se.xual phase, is repeated at very frequent intervals, so that they multiply with enormous rapidity. The nutrition of the bacteria IS derived by a process of direct absorption from the surrounding •7S :f % 176 ANATOM\ OF THE GYMNOSPERMS medium without the development of specialized organs for that purpose. Owing to their minute size they are readily distrib- uted by even slight currents of air, from which they eventually settle as constituents of dust. Their spores offer a remarkable degree of resistance to ordinary conditions, whereby they may survive a most adverse environment for prolonged periods, and again produce the vegetative form when favorable conditions are once more established. It ill thus be observed that the growth and operation of such plants is not necessarily continu- ous, but that their action may be intermittent or periodic, as determined by the special circumstances under which they are placed. In any event, the characteristics noted favor, in an exceptionally high degree, the wide prevalent- of the effects of which they are the immediate cause. It wouiu be out of place here to enter upon a detailed discussion of these effects, and it will suffice to direct attention to the very general relation of these plants to the production of disease in both plants and animals, while their relation to the disorganization of organic tis- sues is exemplified in the various processes of maceration which constitute so essential a feature in many important industrial processes. The second group of plants includes the Fungi, — plants distinguished by their somewhat higher degree of organization and the development of specialized organs. They are generally multicellular, and the pjant body, or mycelium, is in the form of a septate, or nonseptate and branching, microscopic filament, which is capable of very rapid extension, and which may also brmg about a vegetative propagation by simple subdivision. At certain stages of its growth, as also under special conditions of moisture and temperature, the mycelium gives rise to asexual reproductive bodies, or spores. Such spores are very minute, and are composed each of a single cell. They may or may not arise through the medium of a sexual process, the fungi exhibit- mg a great diversity in this respect, a discussion of which is unnecessary at this time. The spores are generally produced m vast numbers ; they are most readily distributed by the wind DECAY 177 or even by slight movements of the air; their extreme buoy- ancy keeps them afloat for prolonged periods, though they eventually settle as one of the ordinary constituents of dust ; they offer a high degree of resistance to deleterious influences,' and are thus capable of bridging over critical periods, at the end of which they may germinate with great freedom. It will thus be seen that through such spores it is possible /or the fungi to develop wherever and whenever favorable conditions are met with. The life history of the fungi is usually much longer and more complex than that of the bacteria, and while the life cycle often involves both a sexual and an asex-.al phase, the former may not appear throughout a very much prolonged period of development, within which the plant may nevertheless extend with great rapidity and produce all the characteristic effects of its growth. Both the bacteria and the fungi are characterized by the ab- sence of a green pigment, or chlorophyll, and their consequent inability to produce carbon compounds from the carbon dioxide of the atmosphere as a source of energy. With the exception of a few of the bacteria, the energy of aU these plants depends entirely upon the oxidation of carbon compounds previously formed and accumulated by some other organisms, primarily those which contain chlorophyll. It is therefore imperative that such compounds should be derived directly from the nutrient fluids of a living organism, or host, upon which the parasite feeds ; or that it should be obtained as one of the product^ of a decay induced by the fungus or bacillMs which thereby becomes a saprophyte. From the naure of their process of nutrition, saprophytes are generally found within the body upon which they act, and they are thus endophytic. This is particularly true of the bacteria. The more highly organized fungi may live chiefly upon the surface of the body (epiphytic), sending the branches of their mycelium (the hyphce) into the interior parts, where they develop spetiali.red feeding branches {haus- toria), which arise wherever food supplies are to be met with. Or, again, endophytic forms may reach the surface only at certain •78 ANATOMY OK THE GYMNOSPERMS periods of development a .nder special conditions of environ- ment, when they become recognizable without the aid of the microscope by reason of their characteristic fruiting structures. It is further true that in these two groups of plants there is a more or less variable relation toward the source of food supply. This is expressed by the classification long since adopted by De Bary (83), and now generally used with slight modifica- tions, who recognized : 1. True or obligate saprophytes: those which obtain their food supplies from the products of organic decay under all circumstances. 2. Partial ox facultative saprophytes : those which u.sually complete the life cycle as true saprophytes, but which, under special circumstances, may more or less completely but temporarily become parasites. 3- True or obligate parasites : plants which invariably derive their nutri- tion directly from the nutritive materials of living organisms. 4. Partial ox facultative para.sites: those which, under .special circum- stance.s, may become saprophytes, though ordinarily completing the life cycle as true parasites. Among the very large number of parasites and saprophytes which attack timber, either living or dead, it will be found that within certain limits there is a more or less well-defined relation to ti.e organism affected, whereby it is characterized by the growth of special forms. The number of species peculiar to a given tree will be found to vary somewhat widely, and this will in turn be influenced within the limits of a particular species of tree by conditions of environment. Thus \on Schrenk (68, 49) shows that the wood of Catalpa specio.sa is injuriously affected by only two fungi, and the same is likewise true of the red cedar (Juniperus virginiana); but Dudley (14) points to the fact that no less than eighteen species of fungi infest the wood of the hemlock (Tsuga canadensis), of which nine are Polypori and six- Agarics. Again, it is a well-known fact that other fungi, such as dry rot (Merulius lachrymans), are not selective in any particu- lar sense, but by reason of their very cosmopolitan habits they grow within any wood, provided the external conditions of warmtli and moisture are favorable. It by no means follows from the DECAY »79 above statement that all the fungi found in a particular wckkI either produce the same or even similar diseases, that they are equally active, or that they operate under all conditions ; and it will suffice m this connection to again direct attention to the results obtained by von Schrenk in the case of the hardy Catalpa, with respect to which he shows that soft rot produced by Polv porus versicolor (L.). Fr.. rapidly destroys the heartw„od. while the brown rot induced by Polyporus catalp.x. von Schr.. operates throughout the trunk near its base ; and yet again, while these two diseases produce specific and distinct effects in the living tree (68). there is as yet no fungus known which will grow in the tissue of the catalpa wood after it has been cut and dried.— a fact which readily explains the remarkable durability of this wood and its adaptation to purposes where freedom from decay IS a first consideration. 2. Conditions under -.vUich they flourish. In entering upon a discussion of the conditions under which fungi operate in plant tissues, we must assume, as is in reality true in all cases, that the latter contain an appreciable amount of material which may be utilized by the fungus for the purposes of its own nutrition Such food material is always presented by the cellulose sub- stance of the cell wall, which is thereby broken down and grad- ually removed, though this does not occur usually until other and more available forms of food material have been exhausted. ' econd place, the nutrient material stored by the plant wn sustenance, such as the starches and sugars, are - attacked by fungi, and so long as they last the invading ■. „..nism confines its operations chiefly to those regions and particular cells in which such storage is most marked. Apart from such conditions of food supply, which must be held to be of fundamental importance and to be a constant factor under all circumstances, air, temperature, and moisture must also be regarded as essential though variable factors which operate as the real determinants in the growth of the invading organism The active growth of all plants demands an abundant supplv of oxygen. In the vast majority of cases this gas is derived i8o ANAIOMV OF THK (lYMNOSPERMS directly from the air, or indirectly throii^'h the medium of the surrounding fluid, such as water, in which the oiganism may be growing. Such aerobes cannot exist when the supply of oxy- gen from cither of the sources indicated is cut off, since their resi)iratory function is inhibited and all dependent activities necessarily cease. It is true tlat some plants, such as certain of the bacteric , cannot live under such conditions of free aeration, in- asmuch as ihey have become adapted to obtaining their oxygen from the products of organic decomposition, and any access of air or free oxygen at once inhibits their growth. Such anaerobes form a comparatively small but none the less exceedingly im- portant group of plants, and it is a knowledge of these differences in the life history of the organism which enables us to gain an intelligent insight into the operation of the various forms of organic decay. It may be stated, then, that the fungi in general cannot grow exce- ♦ under conditions which afTord a free supply of oxygen, and this fact supplies t' c basic principle on which to found methods for retarding or permanently arresting the oper- ation of fungi. But it will be found in practi«.» that this is further dependent upon the remaining factors of warmth and moisture. In the preceding chapter it has been shown that the spores of fungi, as also those of the bacteria, are capable of enter- ing upon a resting state whereby they become capable of resist- ing very adverse influences, but that they are also capable of once more germinating, sometimes after the lapse of sevc ' years, when again brought under favorable conditions. These conditions are (i) a suitable temperature, and (2) an abundance of moisture. The consideration of a few special cases will per- mit of a clearer conception of the nature and operation of these conditions. That all fungi are not equally affected by the same degree of heat and cold is one of the elementary facts of plant physiology, while it is also equally well known that the same plant will be variously affected according to the special condition of growth in which it is brought under the action of varying temperatures. These facts arc probably illustrated among the bacteria in a DECAY I8t more prominent way thin in any other group of plants, though the general relations also hold true for all the higher Jungi. Thus among the bacteria certain forms have been known to survive a temperature of - lo" C. or even - ioo° C. when the cold is applied for a short time only. On the other hand, Bacil- lus thermophilus thrives vigorously at a temperature of 70° C, while the spores of th( cortmon hay bacillus (B. subtilis), which are destroyed when heated in their nutrient solutions to temper- atures exceeding 100° C, are nevertheless capable of resisting upwards of 120° C. of dry heat. From these and similar well- known examples it may be concluded that the specific effect of varying temperatures is due to the amount of water present in the albuminoid protoplasm, — a conclusion in accord with the reduction of water which is known to take place in a cell when it passes from the active vegetative to the resting state, in which form it manifests its highest powers of resistance to extreme conditions of temperature. This principle finds its further illus- tration in the fact that the vegetative cells of fungi, which con- tarn a maximum of water and are adjusted to certain conditions of temperature, may be readily killed by dryness, for which pur- pose desiccation at the ordinary temperature is often sufficient. Broadly speaking, the bacteria cannot survive a temperature exceeding 50° to 60° C. and in this connection a statement of the thre*? critical points in temperature for a few well-known forms, . iven by Warming, may be instructive: Hay bacillus (B. subtilis) Anthrax bacillus (B. anthracis) Cholera bacillus (Spirillum cholerx-asiatlc.x) Tubercle bacillus (B. tuberculosis) Turning our attention to the fungi, which are more immedi- ately concerned in he destruction of timber, we find that with the exception of certain specialized forms the three critical points m temperature may be state as minimum, i ° to 2° C. ; optimum, I :S»' I l83 ANAIOMY OF IHK liVMNOsi'JlkMS 20° C. ; maximum, 40° C. The relation of moisture and hea; to continued life conforms to the same principle as stated for the bacilli, namely, that the s|x)rcs of rcnicillium glaucum and Rhizopus nigricans rarely gv .ninate if exposed for one or two hours to ;. r which has been heated to a temperature of 70° to 80" C, while they are entirely destroyed at 82° to 84° C. On the other hand, spores which have been heated in their own nutrient fluids to a temperature of 54" or 55° C. completely lose all power of germination (84, 725). Although but little is as yet known respecting the life history of the fungi, and especially the particular conditions under which the germination of the spores occurs, the foregoing facts direct attention to the great divci .ity and wide range of the conditions involved for different species. Fortunately the researches of Hartig have made it possible to gain an insight of a more exact c? ractcr into the operations of one of the most destructive fungi kn. n, the dry rot (Merulius lachrymans), a short account of which may serve as a working basis for all fungi. The spores of dry rot germinate on the surface of damp timber, and the growing plant quickly jxinetrates the tissue; but the germination of the spores demands certain conditions which are fulfilled by the presence of alkaline products, particu- larly those which are ammoniacal. It will therefore be found that locations where there is bad drainage, especially in cellars and stables where ammoniacal products are likely to be abun- dant, offer exceptionally favorable situations for its development. When the plant has once entered upon its course of growth its extension is very rapid, and it thrives wherever the air is con- fined, .varm, and damp, though it is well known that air, i.e. air which is freely circulating and which contains a much lov/er percentage of moisture, will cause the death of the plant in one or two days, except f.i - >ply seated parts. From this point of view it may be obst. ^ed that the disease is readily propa- gated in badly ventilated cellars or in confined areas where air does not freely circulate and there is a tendency to the coilec- fon of moisture. Thus in the construction of the MacDonald DECAY 1«3 Ki.ginecrinK Building at McGill University use was made of very hnc timbers of I)o«gl;,s fir as supf-orting f)cams to carry the heavy fl.K,rs of the upinrr stories. These were seated in cast-iroii. flanged bed |)lates. Within a few years, in the room usetl as a hydrauhc laboratory, the timbers had developed dry rot, which extended upwards from the base for a distance of about one foot. The obvious cause was to be found in the con- fined air and in the accumubtion of moisture ondensed from the atmosphere of the room. In another ca' brought to my notice tlic heavy oak roof timbers of a large ' iding developed an e.xtensivc growth of dry rot. Upon examination it was found that the air of the low attic was confined and no circulation was possible. Openings were at once made at opposite emls and a free circaln.tion establisi -I. The difficulty was speedily removed, and there has been no incurrence of the trouble within a period of about fifteen years. Our k-owledge of the way in which and the condit\)ns under which dry rot oixirates makes it jmssible to apply effective reme- dial measures with intellige. :e. These measures involve : 1. Complete ventilation. 2. Removal of all sources of alkaline and particnlarly of ammoniacal products. 3. A complete removal of all diseased wood. 4- Treatment with .so ne fungicide, such as -iric sulphate, he .ondi- tions are such as to make other remedies in any way ineffecti\ Finally, the observations of Dudley (14. 44). 'liat fungi do not penetrate cedar ties unless there is a ^-.^d supply of air, and that when the latter is cu' . /f the pr ..-h stops, once more direct attention to the naf. of the cttcctive prevent- ive measures. From these considerations it becomes obvious that for fungi in general higher temperatures offer correspondingly more favor- able conditions for growth, which is also accelerated fy an in- crease of moisture, both operating within certain well-defined limits. And we may further conclude that preventive measures will be most effective under those conditions which involve low 1 84 ANATOMY OF THE GYMNOSPERMS temperature, an absence of moisture, and, if possible, a complete exclusion of oxygen. 3. Their mode of operation. The mycelium, or plant body, of the fungus consists of a very slender thread which is about 7 M or less in diameter. Comparing this with the normal phys- ical openings in the tissue of coniferous woods, it is found to be only one fourth the size of the cavity of the tracheid (28 /i) of the spring wood, while it is but little smaller than the average tracheid cavity of t!:e inner summer wood (10 ^), and twice as large as the cavities of the tracheids last formed (3.5 fi) in the wood of Juniperus virginiana. Within this same species it is but little smaller than the tangential diameter of the ray cell (8.7 /i,), while it is about twice as large as the average pore of the bordered pit (3.5 /*). Red cedar was selected for compari- son for thf reason that the structural features referred to are relatively small and they represent what is common to a number of species, such as those of Torreya and Taxus. But it must be remembered that in the majority of coniferous woods the open- ings referred to are far larger, and they would therefore offcT correspondingly more favorable conditions for free development of the mycelijm. From these facts it is not difficult to perceive that when spores germinate on the surface of a timber, on a wounded surface, or in a crack, the growing plant at once finds ready access to the interior parts through the natural channels afforded by relatively large openings in the tissue. Such entrance will be greatly facilitated in proportion as the surface is rougher or the tissue is in any way lacerated, since such laceration not only increases the size and number of the initial openings but is also a factor which contributes to more speedy disorganization of the organic substance of the cell wall. From this it is evident that the stumps of branches which have been left in a ragged condition either through wind pruning or through the careless operations of the forester must afford conditions highly favor- able to the operation of decay. Or yet again, when felled timber cracks offer inviting places for the the process of drying before it is rafted, the cracks lodgment of fungus spores, especially Decay '85 those of the rdypori, which abound in the forests. The sub- sequent immersion of the logs as they are floated to the mill causes the cracks to close and favors the development of the spores in the interior of the log. The relatively small amount of fungus developed under such circumstances lies dormant and is widely distributed wherever the prepared lumber is used for constructive purposes. If such boards should be employed in damp and close situations, such as a cellar or poorly ventilated basement, the fungus will find most congenial conditions for renewed and vigorous growth, and all the characteristic phe- nomena of dry rot will be manifested. An instance of this kind came under my observation some two years since in a city house, where the wainscoting of the basement dining room was once removed ; but as the fungus again appeared within a short time and attacked the entire sheathing, the tenants sought safety in removal to another and better constructed house. A second case of the same sort was brought to a conclusion during the past summer. As a precautionary measure, about a year ago the infected woodwork was all removed and the surrounding walls were cleaned as thoroughly as possible, the surfaces being washed with a solution of cupric sulphate. Eventually, it being found impossible to check the trouble without much more exten- sive repairs than the landlord was willing to make, the tenant brought suit and secured damages. When the fungus has once been established through any of the means described, and the conditions continue favorable, it extends with great rapidity in all directions from the original center, being guided in the course it takes by conditions of nutri- tion rather than the path of least resistance, carrying with it all the characteristic features of disease and decomposition. Wher- ever there is room for expansion, as in seasoning cracks or in the cavities arising through its own operations, the mycelium increases greatly and gives rise to massive developments of various forms. Thus in the white rot of the red cedar, caused by I'olyporus juniperinus, von Schrenk has shown that the cavities arising through the action of the fungus are lined with a felt 1 86 ANATOMY OF THE GYMNOSPERMS of soft brown mycelium, which often assumes very fantastic shapes (69, lo). In the diffusion of a fungus through woody tissue two impor- tant features may be noted: (i) the extent and direction of development are determined in the first instance by the distribu- tion of food materials ; (2) the distribution and progress of the mycelium are independent of the presence of physical openings in the structure. A few specific illustrations may serve to malce these statements clear. No matter what particular channels may have permitted the mycelium to gain access to the interior, its development appears to arise chiefly and first of all in the medullary rays. The mycelium extends in the general direction of the ray structure and therefore at right angles to the principal lines of structure for the wood as a whole, filling the individual cells with loosely felted masses of brown hyphae, from which are developed short and variously divided branches. These latter are particularly connected with the absorption of food substances, and they are appropriately known as haiistoria. It very fre- quently happens that such growths of mycelium may be nearly or altogether confined to the structure of the r.iy, the adjacent tracheids being wholly devoid of them ; or there may be local areas within which the mycelia extend vertically upward and downward from the ray, invading the neighboring tracheids, through which they extend for long distances. These facts suggest that the medullary ray may ofifer more favorable condi- tions for development than other parts of the structure, and they make it desirable to ' .nine its structural features some- what more closely from this point of view. An examination of a medullary ray as exposed in radial sec- tion shows that the upper, lower, and side walls — particularly the latter — are provided with definite pits, through which it would be possible for the fungus to jiass into adjacent cells with very little opposition. But such favorable condition^ are obvi- ously not taken advantage of to any great extent, since neigh- boring tracheids often remain quite free from the mycelium while the ray cells are crowded with it. This would seem to DECAY ,87 imply that there is some special property in the ray itself which favors a more vigorous growth there, and serves to retain the fungus in that particular locality. The terminal walls, as in Abies, I^rix, Picea, etc., are perforated with numerous pits, which would offer a somewhat easy path for the radial extension of the fungus. But such openings fail to satisfy the conditions and explain the great abundance of mycelium found in the rays, since the terminJ walls of the Cupressineae are not pitted but present a blank wall to the further progress of the fungus. Furthermore it may be shown, as will appear very shortly, that physical openin^o offer no determining influence upon the direc- tion of growth of the mycelium, which continues in the originally selected course without respect to the structural characteristics of that which may lie in its path. From these facts, then, it would seem that the structure of the ray does not afford an adequate explanation of the observed phenomena. The medullary ray constitutes perhaps the most important structural region within the vascular cylinder with respect to the accumulation of reserve food. This is deposited in the form of starch and other easily assimilated products, and it is their presence in relative excess which undoubtedly determines the abundant development and localization of the mycelia within such regions in the first instance. If this hypothesis be regarded as a correct one, then it is possible to see how the -nycelia gain access to other structures exactly in accordance with its require- ments and the possibilities of finding fresh stores of food mate- rial, which may be held to appear in diminishing quantities as successive areas are entered, until, the more available forms of food having been exhausted, the cellulose fabric itself is attacked, and with its disintegration the characteristic features in the operation of the fungus are expressed in recognizable form. In confirmation of the view thus expressed, it will be found to be very generally true that next to the medullary ray the greatest development of the mycelium takes place in the tracheids and resin passages, which tiiey traverse in a longitudinal direction (plate 9). In this case it is possible that the opportunities for 1 88 ANATOMY OF THE GYMNOSPERMS free growth afforded by the long cavity of the tracheid or resin passage may serve somewhat to influence the direction of growth as the fungus searches for food, although, as in the previous case, it cannot be regarded as a determining factor of primary importance, inasmuch as there is a constant tendency to the formation of branches which traverse the wood at right angles to the walls. The third phase in distribution is established when the vertical strands give rise to hyphae, which are developed at right angles to the original course, and which then traverse the tissue at right angles to the principal lines of structure (plate lo). It might be supposed that the courst of the fungus would be determined by the presence of physical openings in the walls of the tracheids, and that the myce- lium would therefore follow an irregular course leading it through the various bor- dered pits, which, as previously shown, offer ample opportunities for such pas- sage. Such, however, is in no sense the case. In fig. 48 a radial section of the red pine (Pinus resinosa) shows very clearly that the growth of the fungus is wholly independent of physical openings of any kind, otherwise it would take advantage of those which lie in its immediate neighborhood. On the contrar>', its course does not deviate from the original direction established at the point of emergence from the main filament. Whenever in Its progress the mycelium comes in contact with the cell wall, its enzyme attacks the latter, and by solution establishes an opening through which the fungus passes. It will be noted, nevertheless, that the resistance offered by the wall is sufficient to bring about a great reduction of the mycelium, which is always much less than the normal diameter within the limits of the wall. In thin-walled cells, where little resistance is offered, the opening thus established is commonly larger than the mycelium, Fio. 48. Pinus Kr jinosa. Hadial section showing the progress of a fungus mycelium across the line of s>-ucture, and its pene- tration of the cell wall, independently of the presence of pits, x 350 r^^ DECAY ,89 which then has a perfectly free passage; but in all highly lignified tissues, and more particularly those in which secondary growth of the wall is excessive, such contraction is always exhib- ited. This action of the mycelium in perforating the cellulose wall is by no means exceptional or peculiar to the fungi, since it appears in a variety of forms th^-ughout the plant world and constitutes a well-known process in the liberation of spores from the mother cell, as well as in the progress of the pollen tube through the structure of the style. It now remains to inquire somewhat more particularly into the specific action of fungi as expressed in 4. Their effects upon the structure and their relation to forms of preservation in fossil plants. While the general course of the physical changes in decaying wood is fair] well known, ':here are many features which demand more thorough and extended study. This is particularly true of the change." which arise in the ctUulose an^ eventually resolve it into its proximate ele- ments, whereby the chemistry of decay is recognized as one of the mo!.t obscure problems with which the plant physiologist has to deal Nevertheless reference to the well-known reactions for cellulose, as already given (p. 49), enables us to form some con- ception of the nature of these changes, since those which pro- ceed from the action of fungi are in many respects parallel with those obtained through the action of reagents. The alterations accomplished by the latter, either through the action of an acid or of an oxidizing body, are brought about in the fungi by the action of special ferment secretions included under the general name of enzymes. But here it is to be noted that each funj,us behaves in a way peculiar to itself, and gives rise to specific effects which cannot be associated with other fungi. These differences may be reduced in the first instance to two groups, in the first of which the action is primarily upon the intercellu- lar substance, whereby the latter is destroyed with a separation of the secondary walls from one another ; in the second place the action is upon the secondary Walls, which are largely removed with the production of a skeleton composed of the primary igo ANATOMY OF THE GYMNOSPERMS walls. The specific action in such cases is prubably one of hydrolysis, whereby the cellulose is resolved into soluble prod- ucts of the general nature of glucose, and the results are pre- cisely parallel with those produced by Mangin's maceration or by strong sulphuri: acid. But such changes shouH ^. studed through the recort^s of special cases. Tubeuf (72, 38-39) has shown that Trameies pini acts in the first instance upon the more highly lignified portions of the wall. The first effects of its operations, therefore, are expressed in the solution and removal of the primary wall, while the secondary and tertiary walls remain behind as a skeleton, which may eventually become corroded and disappei»^<"^>y "blong orifice. Terminal walls of the ray cells strongly pitted. p„.;„ 11 '7. Tsuga Mertensiana (p. 270). r:t,i;::rg'"°"°''^*'°'^^""°"*'^^ •9S 196 ANATOMY OF THE GYMN06PERMS n ii PlU on th« kitral walU o( iht ray c«ll> imall, «impU. ttliptlcal. Tarminal walla of iht ray ctib mora or !••• iirongly i?Uiad. 16. AbU* (p. J5J). B. RaPin paaaagas and funlform ray* wholly wantinf. I. TraehtUJa (radial or iangtntlal) b« ring thin tpiral bands in 1-4 aariaa. Ray calla (tangantlal) narrowly oblong. Trachaid. (tranavarta) chiafly thick-walled and variable, the lumans usuall* conapicuoualy rounded, the structure somewhat compact (except T. flori dana), the spirala rather close. ' Kay cella (tangential) broad, oval, or oblong. Timchaidi (transverse) Urge, chiafly squarish, and rather thin walled, the atnictura rather open throughout, the spirals rather open. 5. Torreya (p. jio). II. Tracheida (radial or tangentUl) wholly devoid of spirals. I. Wood nonresinous, commonly bearing idioblast* with sphere cryatala; the tracheida of j kinds (transversa). 4- Gingko (p. J09). a. Wood resinous, devoid of crystal bearing idioblasts ; the tracheida (transverse) all of 1 kind. Resin cella (transverse) prominent and in more or less conspicuous, taneeiiiii.! bands, sometimes of distant growth rings or again widely scattering Termmal walls of the ray cells entire, straight, more rarely curved. PlU on the lateral walls of .he ray cell, large, with a dUtinct border Resin cells distinctly zonate. Pi's on the lateral walls of the ray cells round, the narrowly oblong orifice distinctly diagonal, the border very prominent. 10. Taxodium (p. 217), Reain cells scattering. Pita on the lateral walls of the ray cells oval, the oblong orlen ticular onfice usually parallel with the cell axis, the border often narrow, sometimes ob.scure. 13. Sequoia (p. 223). Terminal waib of the ray cells sparingly pitted. Pita on the lateral walls of the ray celU wholly simple or with an incn spicuous border, chiefly small. Rays (tangential) broad, very sparingly resinous, often 2-seriate at least m part. II. Libocedrus (p. 219). PiU on the lateral walls of the ray cells distinctly bordered Rays (tangential) usually rather narrow, more or less stronely resin- ous, I seriate. " ' 15. Juniperus (p. 244). Terminal walls of the ray cells entire or locally thickened, usually much cu, v -d, sometimes straight. ' , ^ 'ftBfg'fflfflE'it* SYNOPSIS OF (;enera 197 "^moillnUn^""*' """'' '" '^'^' '"""^ *"•'' *'•"•'*"«• *«»•• Ray cell* (Ungtntial) narrowly obiong. li. Thuya (p. 220). Ray cell. (langantUl) rathtr broad. ih« c.ll. round, oval or Iran.- v«r»ely oval, rarely oblong. Summer wood uiually ihln and of open itructure Pit! on the tangential wall, of the lummer trachelda uiually large and open, prominent. Rayi (tangential) not ttry numeroua. 14. Cupretaua (p. iiX). Rayi (tangential) ter)> numeroua. 9- Podocarpua (p. f6). Pi«a on the tangential walla of the aummer truheida very nat and not very prominent. 7. Thujopsia (p. J15). SuiT'Mr wood dense, the .pring wood open, thin walled. _ , , 8. Cryptomeria (p. ji6). Terminal wall, of the ray celU thick, more or leu coaraely pitted. Re»in cell. (tran.ven.e) not very prominent, remote, and more or le*. :X rAblLr"" '"" °' "• •""""" ''°°'' •°'"-""" """"^ Ray. (radial) without tracheid. (rarely present in A. baUamea) • 6. Abies (p. 153). Resm celU (transverse) rather prominent, more or le.-. numerous on the outer (ace of the summer wood, rarely lonate. Rays (radial) with conspicuous tracheid*. 1. • '7' '''•UR* (p- 2>jS). KeMn cells (transverse) entirely wanting, being sometime, replaced by resinous StX "' '''''' '""'"* "'°"« '•" »«»"»"> «y«. " --«'-. Bordered pits multiseriate, hexagonal. Restn when present contained in tracheid. (transverse) and foriping pUtes (radwl) simulatmg Sanio's bands, or opposite ray. (tangen. | Growth rings not determinable. Tracheid8(transverse) chiefly equal and in very regular radial rows. I. Cordaites (p. 198). Tracheids (transverse) very unequal and in irreguUr, radial rows. 3. Ataucaria (p. 203). Growth rings obvious, but poorly defined. n J . . . 3' L)<>mmara (p. 201). Bordered pits in i 'ow. *^ ■*' Resin wi^n present contained m tracheids (transverse) and forming plate* (radiai) simulating Sanio's bands, or opposite rays (tangential). Growth rings not very well developed. 0 . . 3 Araucaria Bidwillii (p. 20J). Kesm when present massive (radial), not in plates. Growth rings very prominent and well defined. 16. Abies (p. T53). 1 . «!• 198 ANATOMY OF THE GYMNOSPERMS I. CORDAITALES Growth rings rarely well defined. Wood more or less resinous, but devoid of specialized resin cells or resin reservoirs. Medullary rays all of one kind Bordered pits on the radial walls of the tracheids, hexagonal and multiseriate 1. * • COROAITES, Unger. Plates 12 AND 13 Transverse. Pith of the Sternbergia type, the cells large, thin-walled, often resinous. Growth rings, when present, obscure, rarely somewhat conspic- uous. Specialized resin cells and canals wholly wanting except in the bark, where they take the form of tubular, branching canals without epi- thelium, extending in the general direction of the stem-axis. Tracheid.s *. JV^§^' ''*^'!' r"*"' ™nsP'cuously squarish, and often resin bearinir Kadial. Elements of the protoxylem spiral and scalariform, and often show- ing a graduated transition into tracheids with bordered pits Tracheid.s with hexagonal, bordered pits throughout, on their radial walls only, m i-s rows. Ray cells usually of one kind only; the upper and lower walls thin and not pitted ; the terminal walls thin, not pitted, generally curved ; the lateral walls with bordered pits generally Tangential. Medullary rays rather numerous, i-seriate or often 2-seriate in port. This genus is wholly extinct and occurs only in Paleozoic strata. For a more detailed account of the thirteen known North American species see Penhallow, North American Species 0/ Dadoxylon, Trans. R. S C ' VI, iv, 51-97, 1901. Synopsis of Species The following synopsis is given provisionally as an aid to identification of the various species, without implying the absoli-te value of the differenti.il characters. I. Crmvth rings present I. C. pennsylvanicum. II. Growth rings obscure or obsolete A. Ray elements of two kinds, tracheids and parenchyma Bodered pits in 2-3, rarely 4, rows. Ray cells (tangential) oval or oblong, often narrow. 2. C. Clarkei. B. Ray elements of one kind only Bordered pits in groups of 6-13. Pits on the lateral waUs of the ray cells 3-6, chiefly 4, per tracheid. 3. C. Newberryi. CORDAITES 199 Bordered pits in one row, compressed. Ray cells (tangential) broad, round, or squarish. 4. C. recentium. Bordered pits in 1-3, chiefly 2, rows. Ray cells (tangential) broadly oval. Ray cells about 31-57 /i broad. 5. C. hamiltonense. Ray cells about 28-37 yn broad. Pits on the lateral walls of the ray cells about 1-4 per tracheid. 6. C. illinoisense. Ray cells (tangential) oval or round. Pits on the lateral walls of the ray cells 1-8, chiefly 2-3 per tracheid. ' 7. C. materioide. Ray cells not determinable. 8. C. annulatum. Bordered pits in 2-5 rows. Ray cells (tangential) oval or oblong. Pits on the lateral walls of the ray cells 2-4, chiefly 4, per tracheid. 9. C. ouangondianuni. Pits on the lateral walls of the ray cells 4-10, chiefly 6, per tracheid. 10. C. acadianum. Ray cells (tangential) broad or squarish. Pits on the lateral walls of the ray cells 2 per tracheid. 11. C. ohioense. Ray cells (tangential) oval or round. Pits on the lateral walls of the ray cells 1-5, chiefly 1-2, per tracheid. 12. C. materiarium. Bordered pits in 5 rows. 13. C. Hallii. 1. C. pennsylvanicam, Dn. Transx'erse. Tracheids 44 x 44 ^ broad, the walls 6.7 ^ thick. Growth rines present, the summer wood about 8 tracheids thick, the tracheids about 12.5 fi. radially, the walls 3.1 y, thick. Resin passages and resin cells wsntinir. Radial. Ray cells all of one kind, conspicuously but gradually narrower toward the ends, equal to about 3 tracheids ; the lateral walls with round or oval pits, about 2-3 per tracheid. Tangential. Rays medium, broad, the cells round or transversely oval, vari- able, 25-31 abroad. •' ' The Carboniferous at Pittsville, Pennsylvania. 200 ANATOMY OF THE GYMNOSPERMS 2. C. Clarkei, Dn. Transverse. Growth rings obscure or entirely wanting. The tracheids about 41 X 49 ^ broad, their walls 12.5/1 thick. Radial. Bordered pits numerous throughout the tracheids, in 2-3, more rarely in 4, rows. The elements of the medullary rays of two kinds ; the parenchyma cells thin-walled and devoid of pits, about equal to 3 tracheids ; the ray tracheids long, interspersed, and bearing on their lateral upper and lower walls numerous crowded, bordered pits. Tangential. Rays very variable, commonly i -seriate but sometimes 2-seriate in part ; the tracheids usually distinguished by their narrow form and pitted walls. Hamilton Group, Ithaca, New York. 3. C. Newbenyi, (Dn.) Knowlton Transverse. Tracheids about 44X 55 /*, the walls about 12.5 ^ thick. Radial. Ray cells resinous and starch bearing, long and narrow, about equal to 3-7 tracheids, tl:- ends conspicuously narrower; the pits on the lateral walls 3-6, chiit»y 4, per tracheid, the slitiike orifice nearly the full diameter of the pit. Bordered pits numerous, round, about 9.3/1 broad, distributed in radially disposed groups of about 6-13; the ori- fice diagonal, neariy the diameter of the pit. Tangential. Rays of medium height, i-, 2-, or rarely 3-seriate in part ; 24-55 /* broad, the oval or round cells all thin-walled. Hamilton Group (Middle Devonian) of Ohio (Newberry) ; Carboniferous of Ohio (Claypole). 4. C. recentium, Dn. Transverse. Tracheids 47 x 53 /i broad, the walls much reduced by decay Radial. Ka.y cells all of one kind, about equal to 2 tracheids ; the lateral walls with round pits about i (?) per tracheid ; the cells conspicuously narrower at the ends. Bordered pits in a single row, compact, large, compressed, and transversely oval or oblong, 15.6 x 22 /a, the orifice very variable from oblong to round, often eccentric, but typically round and central. When distant the pits are round and smaller. Tangential. Rays medium, i-seriate or 2-seriate, the very broad ceUs 41 u. thin-walled, round, and squarish. The Permian or Permocarboniferous of Prince Edward Island. 5. C. hamiltonense, Penh. Transverse. Tracheids very variable, growth rings obscure. Radial. Structure of the medullary rays not determinable. Bordered pits hexagonal, in 2 rows throughout. Tangential Rays numerous and variable, 31-57 /i broad; the cells very variable in form and size, thin-walled, often broader than high, chieHy i-seriate, often more or less 2-seriate. Genesee shales (Hamilton Group) of Ontario County, New York. CORDAITES 6. C. illinoisenae, Dn. 20 1 '^"etiiJanT^^iT"'" °' '-^^ '"^"- '^' ^''"'y oval, '"Ti^rf?,,*.''*""''"' °' ""■' '^'»'""'' Ka"». i .he Coal M.„«,es of Rock Ijland, Illinoi., and Boonsboro, Iowa (I). "'meajuresol 7. C. nuterioide, Dn. ''""SjH„^"*Skto"„k,?:i-.> '■™"'' "■= ••«» - ' " «-i=i- *e kniicula, o, oblong S5 n.I?lv ^Uf ^tb. J- '"^' >"' i™'"'" ■ Bordered pte hexaRonll, In "".X^'" ^wf' ''"™'" ■" *= P"' "rn!'5fB™i"';;-::'r;,i',r-~'-^-"-- 8. C. annulatum, Dn. "~^oSrdZ''co*bl&dt=cr«?S"Ss'i^-r; yf „/,'^ V,-" ' '"'""'; ";= ""'» "'°* "Itenuated by decay *""Srb™"rin1-tchiS;2;r1-"'-"'- '-*"^ P"- ^".«on„, '""■Sr,h JStaKEi ■" »""■ "-^ "y O-y '»<■ P'e...re ,„ Middle Carboniferous, Joggins, Nova Scotia 9. C. ouangondianum, Dn. ^™rnon^e"''^''^ =''°"* '' "^ ^' >- •'^-'^' ^"^^ -"« 9-3 M thick. Growth AW/a/. Bordered pits numerous tliroughout the tracheids in -> . rhi.a Middle Devonian of New Brunswick. , 'wM^ 202 ANATOMY OF THE GYMNOSPERMS 10. C. acadianum, Un. Transverse. The large tracheids are about 62 x62 ^ broad, the walls 9.5/1 thick. Scattering tracheids show resinous contents. Radial. Ray cells often somewhat abruptly contracted at the ends, equal to 2-4 tracheids; the lateral walls with numerous round or oval pits, 4-10 per tracheid, chiefly about 6, the border often very narrow, the oblong orifice three fourths the diameter of the pit. Bordered pits numerous, hexagonal, 12.5-16 /* broad, crowded in 2-5 rows. Tangential. Rays very variable, ranging upwards of 60 cells high, resinous, more or less 2-seriate throughout, the oval or oblong cells 17-31 fi broad. Middle Coal Measures, Joggins, Nova Scotia ; Port Hood, Mira, ai J Glace Bay, Cape Breton ; Dorchester, New Brunswick ; St. George's Bay, Newfoundland. 11. C. ohioense, Dn. '''ransverse. Tracheids 47X 56 /x broad, the walls 12.5 fi. thick. Radial. Ray cells chiefly short, about equal to 2 tracheids, straight, or somewhat abruptly contracted at the ends ; the pits on the lateral walls oval, with a promine. t border, apparently 2 per tracheid, but not exactly determinable on account of extended .lecay. Bordered pits in 3-4 rows, sometimes 2 rows throughout the tracheid, hexagonal, abi, . 12.5 ijL broad. Tangential. Rays numerous, upwards of 25 cells high; broad, about 41 j.., conspicuou.'y squarish, i- or often 2-seriate or 3-seriate in part. New Lisbon, Ohio. 12. C. materiarium, Dn. Transverse. Tracheids 45 x 75 /i broad, the walls 7.8 n thick. Scattering tracheids show resinous matter. Radial. Ray cells straight, somewhat narro ved at the ends, eo-.al to about 2-6 tracheids ; the pits on the lateral wal s large, oval, round, or oblonj;, narrowly or even obscurely bordered. 1-5, chiefly 1-2, per tracheid. Bordered pits numerous throughout the tracheids, chiefly in 2, some- times in 3-4, rows, hexagonal, or, when more distant, oval, about 12.5 fi broad. Tangential. Rays i-seriate or 2-seriate in part, upwards of 40 cells high, the oval or round cells 17-35 !>■ broad. Holmes County, Ohio (Newberrj-) ; Upper Coal Measures of Malagash, Pictou, Joggins, Belen, and Cambon, Nova Scotia ; St. George's Bay, New- foundland ; Mirimichi, New Brunswick ; Glace Bay, Cape Breton ; Marion County, Illinois. 13. C. HaUi, Dn. " Wood cells very large, with 5 rows of contiguous, alternate, hexagon.i! areoles. Medullary rays frequent, and with as many as 30 rows of cells superimposed " (Dawson). Middle Devonian of Ontario County, New York. t. araucaria 2. •DAMMARA,' Lami.. Platf.s 14 and ij 203 1- D. austndls, Steud. Kauri*. CowdU Pin* walled passing gradually into the spring wood. Spring wood of tt and lower wa "s th.n and not pitted ; the ten^inal wails U>in 'and en'^ke not locally thickened ; the lateral walls with round, bordered dUs and a fadfZ ihickenei" ''""'^' '"^ ^'l *^^^'^^"^- Wo^tra'heid' usually TSte t"hf.:^ "^" ::*^°'i^ ^''^''^^ The LZutrays strictly thirwS;^ot"too'r'' ""^'^"^'' °^^' °' '^^"— > --'. t£ • ARAUCARIA, Juss. Plates 16 and 17 Framverse. Growth rings not determinable, Resin passages and specialized resin c bearing tracheids more or less promii luuUal. Rays wholly devoid of trache-'ds 1 multiseriate. Spiral tracheids wholly wai. lan^^enttal. Fusiform rays wholly wanting. ' The genus Protodammara ha.s been created by Hollick and Jeffrey for the reception of certain cretaceous cones, but at present it does not contain an/.^od ■ at most poorly defined, entirely wanting. Kesin- d pits usually hexagonal, J04 ANATOMY OF THE (lYMNOSPERMS Synopsis of Species I. ARAUCARIA Existing species confined to tlie southern hemisphere and unknown in the fossil state. A. Growth rings obscure or wanting Bordered pits in 1-3 rows, hexagonal. Resin-bearing tracheids (radial) wanting. 1. A. Cunninghamii Resin-bearing tracheids (radial) numerous, the resin in thick plates like Sanio's bands. 2. A. excelsa B. Growth rings obvious Bordered pits crowded in i row, more or less rounded, not strictly hexagonal. Rays (radial) locally and strongly resinous, the lateral walls at such points with sieve-plate structure. 3. A. Bidwillii II. • • ARAUCARIOXYLON Extinct species occurring in Mesozoic and Tertiary strata, the remains bei.ig usually silicified or calcified. A. Growth rings obscure or wanting Bordered pits in r 3 rows. 4. ♦ • A. Woodworthi. Bordered pits in 1-2 rows. 5. * • A. virginianum. Bordered pits chiefly in i row. Growth rings wholly wanting. 6. • * A. Prosseri. Growth rings present but obscure. 7. * • A. arizonicum. B. Growth rings obvious Bordered pits in 1-2 rows. 8. • * A. Hoppertonse. Bordered pits chiefly in I row. 9. • • A. Edvardianum. Araucarioxylon cbscurum of Knowlton {Mesozou Floras of the United States, p. 418) does not belong here at all, but is cited now for future reference. ARAUCARIA ao5 1. A. CnimiiigluunU, Sweet. Af^^eion Bay Pin,. Hoof Pin,. Colonial Pin,. Cooron,. Cun,H.r,u. Coonan. Transvene. Growth rings not clearly discemihi.- ■ ,r,^k.ij T:i:Z^'i^^^lt^^^''^^^- Pi- on theXntial-wXo] '''''Cpart-''the'ceirr'''.'''" *" '"*'''""'■ '•"'"''"•''= ''"'•retimes ^-seriate wX thin "^ ^^'^^- ""•='!"'"' ''^=»' «^ transversely ova?; the 2. A. excelsa, R. Br. A'orfolk Jslaud Pin, Transvfrse. Growth rings not detprminnW^ . .i,„ • . 3. A, BidwilUi, Hook. Bunya-Bunya '^'"Sure^inTh^'j'T '""""'^ ^"' ^^^^'^ ''^"""^'^ ^y a .slightly more open out IkI f '''■'y fP""S wood : the structure rather dense throuX Ssnotv.r ^-'^''^'f" ^hick-walled, round-hexagonal MeduS roiroTtrrKr'"'"'' '°*^^'>' ^^--^ ^"'"°"-^' • «» ''de, distant" ^ "'''IL'^nrcet'^tTonV;^^^^ ^""'' ^^"'^' ? "^^^^'^'^^ "^ ^ tracheids ; the unn^r in^i ^^ resinous ; conspicuous!) contracted at the ends • ™ir" ■^L^lnuS'.'SSr.^Sr'- gn, marginal cells forming high, vertical series. WhJre resin i; J; a ■« \\ 2o6 ANATOMY OF THE GYMNOSPERMS deposited the lateral walls of groups of cells bear numerous rounded pits, giving a sieve-plate structure. Bordered pits crowded in i row, more or less rounded, not hexagonal, as broad as the narrow tracheids. Pits on the tangential walls of the summer wood wanting. Tangential. Rays low, only a few cells high, numerous, resinous ; the cells oval, broad, thin-walled, strictly i-seriate. 4. • • A. Woodwotthi, Kn. " Transverse. Annual ring very obscure and not visible to the naked eye, but on examination under the microscope it is found to be present and to consist of only 2 or 3 slightly smaller and thicker-walled cells. The wood cells are only moderately thick-walled and are quite uniform in size. " Radial. This .section shows to the best advantage the character of the wwmI. Tlie wood cells are shown to be long, sharp pointed, and to be provided with usually 2 rows of bordered pits, although cells are common on which there is but a single .series. Cells on which there are 3 rows of pits are much rarer. When in a single row the pits are contiguous and but slightly modified in shape by pressure. When the pits are in 2 rows they usually occupy the center of the cell and are contiguous and slightly hexagonal ; but occasionally the 2 rows may be slightly se|> arated and then may have the characters of the single rows. When there are 3 rows of pits they are close together and markedly hexagonal. The average diameter of the pits is about 0.015 "!•"■. and that of the inner pore about 0.003 o"" 0004 mm. The medullary rays, as seen in this section, are short-celled, each cell being about as long as the width of z\ wood cells. They are without markings or pits of any kind, so far as can be made out. " Tangential. Owing to pressure in this direction the section is .somewhat distorted and does not show clearly the relative abundance of the rays. The number of cells entering into the composition of the rays, however, shows satisfactorily. It is found that they are in a single vertical .series of I- 1 2 cells, the usual number being 3 or 4" (Knowlton). Material silicified. Specimen from a large, prostrate trunk 20 feet or more in length and over 4 feet in diameter. Richmond Basin (Trias) south of Mosley Junction, Chesterfield County, Virginia (Knowlton). 5. * • A. virginianum, Kn. " Transverse. Growth rings not obvious to the naked eye, but apparent micro.scopically. The line of demarcation consists of only 3 or 4 mus of slightly .smaller and thicker-walled cells. [Growth rings obscure, IJ.P.I'.] Tracheids prominent, with thick walls. The individual lells have a diameter of 0.051 mm., the average being about 0.0375111111. They are arranged in radial rows, which are most pronounced in prox- imity to the medullary rays. " Radial. The radial walls are the only ones bearing bordered pits. 1 lie number of rows varies, even on the same cell, from 1-2. When then i> but I row they occupy the center of the cell and are in contact. Tliev ARAUCARIOXYI.ON 207 are then nearly circular in outline and have a diameter of 0.0.7-0.0: mm X?,„7h,r' ' '°7 'hey are in contact and alternate with each o her and have a nearly regular, hexagonal outline. These hexaironal pits have a d.ameter of 0.0.6-.02, mm. The inner pore i^ very sS being only about .002S-.003 mm. in diameter ^ ' " TaHgential. The ray.s are single and range from 1-27 cells in height the average number being about 10-12 " (Knowlton). ^ ' Material silicified. Specimen represented by a small fragment From the Potomac Formation at TaylorsviUe, Virginia (Knowlton). 6. • • A. PrMwri, Penh. 7>tf/w'*/-.f^ Tracheids in regular radial rows, squarish, 39x42 u broad- the walls 6.2 /.thick. Kesin cells and special res n passages wholK- .. ,.«?"^"S- No evidence of growth rings in fradial extent of f 2 mm ^ ha.i,al. Ray cells all of one kind, .straight or narrower at the ends, equal to 3-9 tracheids; the upper and lower walls thin and devoid of pits- the erminal walls thin, not pitted, curved ; the lateral walls .show no struc- ure through extreme alteration. Hordered pits not clearly determinable but probably round and in 1 row. ^ ucicniundoie, ''"'wide"'' '*''^'' ""'""°"'' ''•'''^"y '"'*■ ! "^« «"s broad, round, about 3. ^ Material silicified. The Cheyenne (Comanche Cretaceous) of the bluff west of Sun City Medi- cine Lodge River, Baker County, Kansas, 1897 (Prosser). 7. • • A. arizoniCttm, Kn. " Transverse. Annual rings not apparent to the naked eye, but under the microscope observed to be present, the yeariy growths being separated by a layer of 2-s tangentially compressed cells; the tracheids in this section are observed to have moderately thick cell wall.s, and to be separated by small intercellular .spaces. The largest cells observed have a dian.-jter of .055 mm. and the smallest of about .020 mm., the average bemg about .040 mm. t uicid^e "Radial As seen in this section the tracheids are obserN-ed to be long, and to be provided with numerous pores. These pores or bordered pits are usually arranged m a single series, and number 40-80 or more on each cell. Usually they touch each other slightly, but sometimes thev become a trifle compressed by actual contact. When these pores are arranged in 2 series they alternate and are .slightly, if at all, angled by mutua pressure. The pores are rather large, the average diameter for the outer circle being about .02 mm., that for the inner .0040 mm The medullary rays are composed of short, thin-walled cells, which, in some in^ances, seem to have been provided with small, oval pores. They are difficult of demon.stration, and it is possible that the granular contents _ ot the cells may give the appearance of exterior markings. tiini;e>,f,al. fhis section demonstrates the presence of pores or bordered pits on the tangential walls, a circumstance of infrequent occurrence I ] 308 ANATOMY OF THE C'.YMNOSPERMS in the genus Araucarioxylon. They are much xmalle' than the pores on the radial walls, and are in a single or rarely in 2 series. The pores are always separated from each other, sometimes widely so. The diame- ter of the outer circle is about .0075 mm., and that of the inner about .0027 mm. The medullary rays are numerous and range in height from 1-22 cells. It is possible that in some rare cases they may be in 2 series, but this is certainly not commonly the case. No resin ducts have been detected in any of the sections, their absence being a well- known character of the genus" (Knowlton). Material silicified. Specimens are represented by fragmenta of trunks upwards of 20 inches in length and 13 inches in diameter. Triassic or Lower Jurassic near Fort VVingate, New Mexico; Lithodendron Creek (Cretaceous?) and Chalcedony Park, Arizona (Knowlton). 8. • • A. Eoppertoue, Kn. " Trann>erse. Annual rings very distinct, of 4-8 rows of very thick-walled fall wood. The .spring wood is made up of very large though thlcl'- walled cells, which begin very abruptly at the fall wood. The cells gradually decrease in siie until the last 5-8 rows of cells are very thick » Radial. A.-* the material has been very finely preserved, this .icction shows remarkably well. The wide cells of the .spring wood are provided with usually 2 longitudinal rows of hexagonal pores, which quite over the walls. Occasionally, in cells of unusual width, the pore-s, while in 2 series, are only slightly compressed. Usually when but 1 row is present they are hexagonal and occupy the center of the cell. The inner ports m these punctations are relatively .small and .slightly elongated in .i direction at right angles to the cell.s. The medullary rays as seen in this section are short, covering the width usually of 4 or 5 wood cells although occasionally longer and covering as many as 8 cells. This are provided with a single row of Ijordered pores so arranged tl.at i comes over each wood cell, or occa.sionally there may be 2 over a wood cell. I he inner pore is minute. " Tangential. The medullary rays as .seen in this section are quite numer- ous, in a single series of from 3 to .sometimes as many as 1 5 superim- posed cells. The wood cells as seen in this section do not seem to have been provided with punctations or other markings" (Knowlton) Material silicified. Cretaceous formation of the Black Hills, Cycad bed 2 miles southeas' of Minnekahta Station, South Dakota (Knowlton). 9. • • A. Edvardianum, Dn. "Trunks with distinct rings of growth, and with a central pith no< observed to have transverse lamin.-e. Wood cells with i or rarelv 2 rows ot contiguous, he-vagonal areolx. Medullary rays simple, infrequent, with 2-10 rows of cells superimposed " (Dawson). Triassic of Prince Edward Island (Dawson). GINGKO 309 II. GINGKOALES Wood nonreslnous, the tracheids of two kinds, intewpcrwd. Wood paren- chyma present and forming idioblasts containing sphere crystals. I. • OIKOKO, Ka.mi'K. Plates 18 and 19 Trantverse. Growth rings broad. The summer wood thin ; the ."Structure " ?^". »*"'°"K*'o"t; tracheids chiefly sc|uari.sh anU large, with 81 thicker-walled tracheids interspersed. Ke.sin passages and resin X. vw '\r"'^' ?■ *''"""« Cr>.stal-bearinK idio».Ia.sts rather numerous Radtal. Medullary rays devoid of tracheids. Terminal walls of the ray cells very thin and not pitted. Hordered pits in 1-2 series. Spiral tracheids wholly wantmg. "^ ^""Cwalled"'^""" "^'' **'°"^ wan'iniiC Kay cells rather broad and 1. 0. biloba, Linn. Afaidtnlmir Tree. Salisburin. Cinato. Jap. = /cho Transversa. Growth rings ver>- broad, the summer woo- narrow and of open structure, passing gradually into the spring wood. Spring wood open, the tracheids large, squarish, very unequal, somewhat thin-walled with which are interspersed less numerou.s, much smaller, rounded, and thick-walled tracheids. Idioblasts containing sphere crystals somewhat numerous. Medullary rays prominent, slightly resinous, i cell broad distant 2-10, more rarely 15, rows of tracheids. ' Kadial. Cells of the medullary rays con.spicuously contracted at the ends locally somewhat resinous, equal to about 5-7 spring tracheids- the upper and lower walls verj- thin and not pitted ; the terminal walls' very thin, not pitted or locally thickened, chiefly straight : the lateral walls with oval, bordered pits having a narrowly oval or oblong orifice, about 1-4, or, in the marginal cells, 7, per tracheid. Hordered pits very numer- ous in the broader tracheids, where they are compres.sed vertically and crowded m i row, or more generally in pairs, forming 2 compact .series; in the narrower tracheids few, round, distant, and often wanting Pits' on the tangential walls of the summer tracheids numerou.s, large, and open Idioblasts round or oblong, 1 sphere crjstal to each ; scatterini: or often in vertical .series. Tangential. Fusiform rays wholly wanting. Rays strictly I -.seriate, low to medium : the cells rather broad, oval, thin-walled, somewhat variable Idioblasts oblong, in vertical series, Native of Japan, now widely distributed through cultivation in similar climates. 2. « • G. pusilla, Dn. Transverse. Growth rings obvious, the spring wood pa.ssing gradually into the not strongly defined summer wood: tracheids in regular radial rows, very uniform, those of the spring wood about 22 x 21 ^ the walls 5-3 Ik, thick. Medullary rays ver}- narrow. fl 3IO ANATOMY OF THE OYMNOSPERMS t ^'*1""»'y •?>?•, ^«T '•"*• "** «"» »«"'«»•». "bout 17 M high eoual o about s tracheid,; the upper and lower walU thin and^ nof pit?H the termina wall.-, thin. MraiKht. and devoid of pit.; the lateral wll' ''""Cd '^'''"""'^ "*■' '■3' ■""'• '"«'y ^' ""- »«'«»'. »bout 8.7 M Material calcified. Upper Cretaceous of Port McNeil, Vancouver Inland, and Upper Creta- ceou. of Cumshava Inlet. Queen Charlotte Lnlands. III. CONIFERAI.ES ./ooa more or less re.,inou». often characterized by the presence of .spec.al.zed re.sin cells, cysts, or passages. Trachcids (transverse) in radial rows, l^arinK on their radial wall.,, as al.« on the tangential walls of the sum- mer tniche.d.s, round or elliptical, often distant, bordered pits in 1-3 series. 1. TORR£YA, Arnott. I'latks 20 ano 21 7>' "^"^ °' °»''°"«- f «'^'^™ ray" -holly SvNOPSis OF Species A. Summer wood thin, of 2-4 tracheids or more, often double • the structure of the growth ring very open throughout Tracheids large, distinctly squarish. Spirals in 2 .series. I. T. taxifolia. B. Summer wood thin but sometimes equal to the spring wood ^ofl'^fn '''^- ""'T'"' ""' •^""•"Pi^-o""'')- squarish, chiefly hexagonal, otten in very irregular rows. Spirals imperfectly 2-4 seriate, often very incomplete. 2. T. californica. Sp.rals in double, triple, or quadruple series. 3. T. nucifera. TORREYA 211 1. T. taxifelk, Amott Stimt$ng CeJar. Savin TraHs.,tr,t. Growth ,%» variale. i? -3 mm. thick. Summer wood of j x or more trache.d^^ually very thIn. often double and pT^inK^adualW no the HpnnKWond; .prinx tracheid» «,uari.h and in 4ular row, a V r.v • J"^"'^«"« "' «he growth rin^ o,H:n throughout Medu-' Radial Ray cclis utraiKht; the upper and lower wallH thick consDir..n...iv pnted uniform ; the terminal walls thin and entire ^eS cur""?- trtT\t """i'" *"*• ■""""• '"""*'• ''"' ^"''^We pit. with a diH incJ boKier. the or.fice ver>. narrow. 2-5 per tracheid. Bordered pitrn, or 2 rowH^ P.tH on the tanRential walls of the .summer tracheids o|«cure Spirals of the tracheids in 2 series, distant 5-30 m. very flat the anJui 70.4». compact and finally ves- -,| in the summerw,^ ' *^'' Cied ^^" " ■ *' ' *■**" •■"'"• °^"'- «' "blonK. thick. Very durable in the soil. Relative specific gravity .... Approximate fuel value .... F,?*,*^!''"* °' ^'a^l'city in kilograms on millimeters. 0.5145 5i.o« 821. Ultimate tran.sverse strength in kilograms ,,o" Ultimate resistance to longitudinal cru.shing in kilograms li^i Resistance to indentation to 1.27 mm. in kilograms jf^" (Sargent) • • . 2523. Western Florida. 2. T. californica, Torr. Stinking Cidar. California Nutmeg Transverse. Growth rings 1.5-2.5 mm. broad. Summer wood thin, some- fK.i •/""'''"'■. "^ '*''= K'°*'*' "»«■'' ^=»'her open throuuhouT the tracheids somewhat rounded and in more or less irregular row ' umI '"^'^ ""*" ^■■°"'"'^"*' ' "" ^"''' '''•^'='"' -'-M rLr^f /•Ww/ Ray cells straight ; the upper and lower walls rather thin con- spicuously double and frequently pitted ; the terminal wal s v r^ thin and entire ; the lateral walls with rather variable, round, bordered pits, 1-6 per tracheid, the orifice very narrow. Bordered pits usuallv somewhat d.stant, elliptical, in , n/w, .sometimes in pairs Pt" on the tangential walls of the summer tracheids smaP and obscure spirals of the tracheids high, often very incomplct.-iy developed mperfectly 2-4 senate, distant 5-125 /x or more, the angle 46 2^.' the summer wood obscure and finally ob.solete rangenlial. Rays medium to low, the cells large, rather thin-walled Si .■ i 212 ANATOMY OF THE GYMNOSPERMS Very durable in the soil. Relative specific gravity 0.4760 Approximate fuel value 46.06 Coefficient of ela.sticity in kilograms on millimeters . . 401! Ultimate transverse strength in kilograms 249. Ultimate resistance to longitudinal cru.shing in kilograms 5625. Resistance to indentation to 1.27 mm. in kilograms . . 1962 (Sargent) Mendocino County, California, and along the western slope of the Sierra Nevadas to Tulare County, at elevations of 3000-5000 feet (Sargent). 3. T. nuciiera, Sieb. et Zucc. Trans7>erse. Growth rings rather narrow ; the tracheids of the spring wood large, often distinctly squarish, passing gradually into the con.spicuous but narrow summer wood of about 10 tracheids, which again becomes equal to the spring wood. Medullary rays prominent, i cell wide, dis- tant 2-10 rows of tracheids. Radial. Cells of the medullary rays not contracted at the ends, equal to about 6 tracheids ; the upper and lower walls medium, remotely and obscurely pitted ; the terminal walls thin, not pitted or locally thick- ened, diagonal or straight, rarely curved ; the lateral walls with small, conspicuously bordered, oval pits with a diagonal, linear-oblong ori- fice, about 2-6, or, in the summer wood, 1 per tracheid. Bordered pits in I series, or in pairs, forming 2 imperfect scries, distant, the outer margin rather ob.scure, the orifice lenticular and diagonal throughout. Pits on the tangential walls of the summer wood wholly wanting. Spirals of the tracheids prominent, distant 5-25 ^, in double, triple, or quadruple .series, the angle 70.5°, in the sumn er wood becoming vestigial in the outer tracheids. Tangential. Rays numerous, low to medium, the walls of the cells rather thick. Pits on the tangential walls of the summer wood wanting. Japan. 2. ♦ TAXUS, TouRN. Plates 22 a.nd 23 Transverse. Growth rings variable, often unconformable. The summer wood dense and conspicuous, though often very thin ; the tracheids small throughout and more or less rounded, the structure .somewh.ii dense or more rarely open (T. tloridana), with large and squarish tracheids. Resin passages and resin cells wholly wanting. Radial. Spirals of the tracheids rather close, 2-, rarely 3-.seriate. Tangential. Ray cells narrowly oblong. Fusiform rays wholly wanting. Synopsis of Species A. Tracheids .small, rounded, thick-walled Rays low, 1 -seriate. Growth rings variable, sometimes double. 2. • T. canadensis, Willd. TAXUS Rays chiefly hiKh, 1-2 seriate. Growth rings usually broad. 3. T. brevifolia, Nutt. B. Tracheids medium, rather thick-walled Rays medium. Growth rings usually rather broad. 4- T. cuspidata, Sieb. et Zucc. ;.". Trachci'Li ! r e, the structure open Rays chiefly hi ,1. I. T. floridana, Nutt. 213 1. T. floridana, Nutt. Yeio Transverse. Growth rings medium, irregularly eccentric. Summer wood very thin, upwards of 10 tracheids thick, rarely double, open ; the tracheids unequal in irregular rows with more or less conspicuous intercellular .spaces ; transition to the -spring wood gradual. Medul- lary rays prominent, i cell wide, distant 1-10 rows of tracheids. Radial. Ray cells straight, rather narrow ; the upper and lower walls entire, more or less sinuately unequal ; the terminal walls thin and not pitted ; the lateral wails with somewhat conspicuously bordered oval or rounded pits, the orifice lenticular, diagonal, chiefly 1-2, more rarely 3, or, in the marginal cells, 4 per tracheid. Bordered pits very scattering except at the ends of tracheid.s, where they become more or less 2-rowed. Pits on the tangential walls of the summer wood small, often very distant, the orifice bell-shaped. Spirals of the tracheids prominent, rather flat, 2-seriate, distant 7.5-20 /ix, rarely more, the angle 78.4°! wanting in the outer summer wood. Tatii^ential. Rays medium to high, the cells very narrowly oval to oblong. Western Florida. 2. • T. canadensis, Willd. American Ye-.v. CrounJ Hemlock Transverse. Growth rings narrow and variable, often unconformable. Summer wood variable, now thin and abruptly pa.ssing into the spring wood, or thickish and finally equal to the spring wood into which it gradually passes ; rather dense. Spring wood more open, the tracheids small throughout and thick-walled but distinctly rounded and variable. Medullary rays 1 cell wide, not very prominent, dis- tant 2-15 tracheid.s. Radial. Ray cells equal to about 5 spring tracheids; the upper and lower walls rather thin, uniform, entire, or remotely pitted ; the terminal walls thin and entire, often curved ; the lateral walls with round, bordered pits, 1-2 per tracheid. Bordered pits small, round. Pits on the tangen- tial walls of the summer wood very numerous but small and obscure. Spirals of the tracheids very prominent, 2-3 .seriate, distant 7.5-15 /*. the angle 72.4°, con.spicuous throughout the summer wood. Tangential. Rays very low, the cells rather thick-walled. i if 214 ANATOMY OF THE GYMNOSPERMS Damp woodlands fiom Newfoundland westward to Lake Winnipeg and Minnesota, northward to York Factory, and southward to New Jersey or along the Alleghenies to Virginia. The Pleistocene of the Don River, Toronto ; Solsgirth and Heart Hill, Rolling River, Manitoba, and Fort Madison, Iowa ; Cape Breton and Bloomington, Illinois. An abundantly represented and widely di.s- tributed species in the northern United States and southern Canada. 3. T. brevifolia, Nutt. Veiv. Western JVw rrann>erse. Growth rings thick, upwards of 2-3 mm. Summer wood dense, about equal to the spring wood into wliich it pa.sses very gradually. Spring wood open, the tracheids in regular row.s, rather uniform, not much rounded. Medullary rays 1 cell wide, distant about 1-17 rows of tracheids. Radial. Ray cells very long ; the upper and lower walls thicki.sh, unequal conspicuously double, entire or distantly pitted ; the terminals walls thin and entire; the lateral walls with round, con.spicuously bordered pits, chiefly 2, more rarely 4, per tracheid, the narrow diagonal orifice equal to the outer ring. Bordered pits round or elliptical. Pits on the tangential walls of the summer tracheids numerous but very small and obscure. Spirals of the tracheids prominent, 2-.seriate, distant 7-5-20 ^ rarely more, the angL 63.0°, vestigial in the summer wood. langential. Rays commo.^lv high, the cells thick-walled. Very durable in the soil. Relative specific gravity Approximate fuel value . . . . Coefficient of ela.sticit in kilograms on millimeters '. . ^u. Ultimate tran.sverse strength in kilograms 460. Ultimate resistance to longitudinal crushing in kilograms 7734 Resistance to indentation to 1.27 mm. in kilograms A-^-y% (Sargent) * " ^~'^' Vancouver Island and adjacent mainland and on the lower Skeena (Macoun) ; .sparingly in the Queen Chariotte Islands (Dawson) ; .south- ward through the coast ranges of Briti.sh Columbia, Wa.shington, ami Oregon, the western slopes of the Rocky Mountains in Montana, and through the California coast ranges to Monterey and the southern .slopes of the Sierra Nevadas to latitude 37° N. (Sargent). 0.6391 63.78 761. T. cuspidata, Sieb. et Zucc. Yew. Jap. = Araragi Summer wood prominent, about Trans7'erse. Growth rings rather broad. __ one fourth the spring wood into which it passes gradualTy "sprrn" wood somewhat open, the tracheids distinctly hexagonal, rather THUJOPSIS 215 uniform and thin-walled. Bordered pits on ilie tangential walls of the summer tracheids few and obscu-e. Medullary rays prominent, 1 cell wide, distant about 2-10 tracheids. - - ■ RadiaL Cells of the medullary rays not much contracted at the ends • the upper and lower walls rather thin, but very une.iual and obscurely ^u-'l ' 'j'^!"'"'"^l «:>lls thin, often obscure, not pitted or locall'y thickened, diagonal and chiefly straight; the lateral walls with con- spicuously bordered pits, oval, with a diagonal, knticular-oblong orifice, chiefly 2 per tracheid in radial series, equal to about 4-0 tracheids. Bordered pits round, about two thirds the width of the tracheid, m open rows, the orifice round, concentric, in the summer wood becoming lenticular, diagonal. Pits on the tangential walls of the summer tracheids distant, rather ob.scure. Spirals of the tracheids 2-seriate, distant 12.5-25 ,*, the angle 66. i", vestigial in the .summer Tangential. Bordered pits on the tangential walls of the summer tra- cheids not very numerous, in distant groups. Rays low to hiuh numerous. * ' % 3. THUJOPSIS, SiEB. ET Zucc. Plates 24 and 25 Transi>erse. Growth rings usually very narrow. Resin passages wholly wanting. Resin cells not numerous but prominent, rarely zonate Kadtal. Ray tracheids wholly wanting. Bordered pits generally rather numerous, in i row. Tracheids wholly without spirals Tangential. Fusiform rays wholly wanting, the i-seriate rays low, resinous 1. T. dolabrata, Sieb. et Zucc. Jap. = Ilibii Transverse. h rings very narrow and variable. Summer wood rather , retimes dense, thin, of 2-10 tracheid.s, the transition to the ood rather gradual. Spring wood very open, the trachtids uge, squari.sh-hexagonal, in very regular rows, uniform, very thm-walled. Resin cells very prominent, not numerous, scatter- ini; throughout the growth ring, not obviously zonate. Medullary rays prominent and resinous, not numerou.s, i cell wide, di.stant ^-1^ or sometimes 16 rows of tracheids. Radial. Rays somewhat resinous. The cells conspicuou.sly contracted at the ends, equal to 5-6 spring tracheids; the upper and lower walls thick, sparingly pitted ; the terminal walls thin, often curved, not pitted or locally thickened ; the lateral walls with .small, obscurely bordered pus, the large orifice broadly lenticular or oval, about \--> per tracheid. Bordered pits round or elliptical, nearly as broad as the tracheid, rather numerous, in 1 row. Pits on the tangential walls of the summer tracheids few, very flat, and rather obscure. Re.sin cells 15-25 /u wide, chiefly 225 /i long. Tangential. Rays low, not very broad, resinous ; the cells oval or oblong, rarely round, rather thick-walled, 1 -seriate. 4 V. f 2l6 ANATOMY OF THE GVMNOSPERMS 4. CRYPTOMERIA, Don. Plates 26 and 27 Trannierse. Growth rings medium, with a dense summer wood and open spring wood. Resin passages wholly wanting. Resin cells prominent and scattering. Radial. H^y^ wholly devoid of tracheids; the cells sparingly, if at all resinous; the terminal walls thin and not pitted or locally thickened Bordered pits in 1 row, much less than the diameter of the tracheid Tangential. Fusiform rays wholly wanting. Cells of the I -seriate rays rather broad, round. 1- C. japonica, Don. Cryptomeria. Jap. = Sugi Transverse. Growth rings medium, rather uniform. The summer wood prominent, about one fourth the spring wood into which it passes rather abruptly, the structure dense. Spring wood very open the large tracheids hexagonal, uniformly thin-walled. Resin cells promi- nent and scattering, chiefly confined to the summer wood and the late spring wood, the resin 6"ing the cells. Medullary rays some- what prominent, distant 2-., ire rarely 20, rows of tracheids. Radial Ray cells more or less conti. ' .. .ne ends, equal 'o s-9 spring tracheids; tne upper and lower w..;s rather thick, uniform, distantly pitted; the terminal walls thin, not pitted or locally thickened, straight or curved ; the lateral walls with round, ob.scurely bordered pit.s, 1-2 ,n radial series or in the marginal cells 3-5 per tracheid Bordered pits one half the diameter of the tracheid, in 1 row, round! the orihce round ; in the summer wood small, becoming obscure or entirely wanting, the orifice a slit. Pits on the tangential walls of the summer tracheids small but numeious. Resin cells upwards of 20 u wide and upwards of 400 fi. long. Tangential Rays all i -seriate, rarely 2-seriate in part ; low, the cells round, rather thick-walled, uniform. 5. PODOCARPUS, L'Her. Plates 28 and 29 Trans^'erse. Growth rings very variable, either very narrow or very broad bum...er wood very thin and not clearly distinguishable from the- spring wood. Structure open, tracheids of the spring wood lart;f squarish. Resin passages wholly wanting. Resin cells numerous,' scattering, rarely zonate. Radial Ray tracheids wholly wanting. Bordered pits small, distant in I row. Spiral tracheids wholly wanting Tangential Fusiform rays wholly wanting. Ray cells oval or round, thick-walled. 1. P. macrophylla, Don. y,;/. = Maki Transverse. Growtn rings very variable and narrow, or again broad. The summer wood very thin and not very different, of 2-4 tracheids and passing imperceptibly into the spring wood. Tracheids of the spring TAXODIUM 217 n^S.^'^'f."*''"*'''"'^"'''''' ""^^ ""if""", •-'nd somewhat thick-walled. Kes n lells very numerous, the resin rhiefly in a peripheral Jayur • oHe«z^nl^:°"''M°H ','.''" «'°""' ""« "^ occasionally becoming more or ess zonate. Medullary rays prominent, numerous, and i cell wide distant 2-9 rows of tracheids. ' Radial. Medullary rays conspicuously resinous, numerous ; the cells not muchcontractedat the ends, equal to about 6 tracheids. The uppe and lower walls thickish, unequal, irregulariy and often distant^ S'!h- f''r'i^''.'''°"'*' '^^ '^™'"^' «■•■»"'' «hi" not pitfed or Sr'^nt'. "''^' '^'"^ '''^"Sly curved ; the lateral walls wfth smaj rather obscure, oval pUs, 1-2 per tracheid, theorif^.e narrowly lenticu la^ often shtl.ke Resin cells very numerous, upwards of 20 /wide Ind 200 ^ long. Bordered pits small, round, distant in . row. Pii. on the rJS Thr."' ""■ '^^ '""""" "°«*^ ""'""°"^' conspicuous, open rangenhal. The i -senate rays very numerous, medium ; the ovalor round cells somewhat thick-walled, rarely in pairs. 6. • TAXODIUM, Rich. Plates 30 and 31 Tratt^n>erse The suminer wood of the usually broad growth rings much less than the spring wood. Resin passages wholly wanthi^ Hesin cells numerous and prominent, either scattering or zonate RadiaL Rays wholly without tracheids, the cells commonly contracted at the ends. Tracheids wholly without spirals i-""iraciea at ^'"'•broadly oval.^"™ "^' '^''""^ ''^"*'"^* "*' ""^ °^ ">« -««"=''« «>- Synopsis of Species Resin cells large, numerous, more or less distinctly zonate Pits on the lateral walls of the rays cells 1-4, mo.* rarely 7, per tra- cheid, the lenticular orifice narrow. Bordered pits numerous, often paired, or in the eariier spring wood imperfectly 2-rowed. 1. * T. distichum. Resin cells obscure and forming an open zone on the inner face of the summer wood. Pits on the lateral walls of the ray cells about 2-3 per tracheid in radial series. Bordered pits numerous.in the eariier .springwood crowded into 2-3 compact rows, but becoming 2-rowed toward the summer wood. 2. • * T. laramianum. 1. • T. distichum, Rich. Bald Cypress. DeciUuotis Cypress Transverse. Growth rings usually very broad. The dense and conspicu- ous summer wood often double or treble; transition to the spring 2l8 ANATOMY OF THE GYMNOSPERMS wood somewhat gradual. Spring wood very open ; the tra( hekls very large, thin-walled, hexagonal, rather uniform. Resin cells nuim r ou.s, large, not strongly resinous, distinctly zonate or sometimes .scat- tering throughout the growth ring. Medullary rays prominent hut sparingly resinous, distant 2-.S or more rarely 13 rows of tracheids, 1 cell wide. Radial. Ray cells sparingly resinous, usually more or less contracted at the ends, equal to 3-5 .spring tracheids ; the upper and lower walls thickish, rather unequal and entire or distantly and often imperfectly pitted ; the terminal walls thin, .sometimes obscure, often curved, not pitted or locally thickened ; the lateral walls with prominent and con- spicuou.sly bordered pits, round, 1-4, or more rarely 7, per tracheid, the very narrow, lenticular orifice often as long as the outer limits of the pit. Bordered pits chiefly elliptical, numerous, variable, often paired and in the earlier spring wood becoming imperfectly 2-seriate. Pits on the tangential walls of the summer tracheids very numerous, not very large. Resin cells sparingly resinous, 25 /x wide, chiefly 140 ft. long, but ranging upwards of 310 /n. Tangential. Rays numerous, medium to high, very sparingly resinous ; the round or oval cells rather broad and thick-walled, rarely in pairs. Wood very durable in the soil and of great economic value. Relative specific gravity 0.4543 Approximate fuel value 45.24 Coefficient of elasticity in kilograms on millimeters . . . 1032. Ultimate transverse strength in kilograms 291. Ultimate resistance to longitudinal crushing in kilograms . 6771. Resistance to indentation to 1.27 mm. in kilograms . . 1166. (Sargent) Material silicified. Delaware to Florida and westward through the Gulf States to Texas; north- ward through Tennessee, Kentucky, and southern Missouri to southern Illinois and Indiana (Sargent). This well-known Tertiary plant, chiefly represented by its foliage and fruit, is known through its woody structure in only one instance, occurring in the Eocene of the Porcupine Creek and Great Valley groups. 2. • * T. laramianum, Penh. Transverse. Growth rings prominent, rather broad. Summer wood promi- nent, upwards of 17 tracheids thick and passing somewhat gradually into fhe broad spring wood. Spring tracheids large, squarish-hex- agonal, thin-walled, uniform in regular rows. Resin cells obscure and fornv"g an open zone on the inner face of the summer wood. Rtsin passages wholly wanting. Medullary rays numerous, narrow, distant about 2-8 rows of tracheids. Radial. Medullary rays wholly devoid of tracheids. Ray cells straii^tit, equal to about 3 tracheids ; the upper and lower walls rather thick LIBCCEDRUS 219 and sparingly pitted ; the terminal walls straight or diagonal, some- times cur\ed, entire ; the lateral walls with oval or rounded pits, about 2-3 per tracheid in radial series. Bordered pits numerous, • becom- ing 2-rowed toward the summer wood, though distinctly crowded into 2-3 compact rows in the earlier spring tracheids. Kesin cells not conspicuous. Tangential. Resin cells conspicuous but not numerous, about 3 times longer than broad. Medullary rays rather numerous and narrow often very high, strictly i-seriate ; the cells oval, more rarely round in the low rays. Material siliciiied. A distinctive species occun'ng in the Laramie (Eocene) at Cochrane, Alberta. 7. LIBOCEDRUS, Endl. Plates 32 and 33 Transverse. The thin and rather dense summer wood usually showing a more dense median layer. Resin passages wholly wanting. Re.sin cells numerous and conspicuously zonate. Radial. Rays wholly without tracheids. The terminal walls of the ray cells straight or curved, entire, locally thickened or even coarsely pitted. Tracheids wholly without spirals. Tangential. Fusiform rays wholly wanting, the rays strictly of one kind. 1. L. decttrrens, Ton-. White Cedar. Bastard Cedar. Post Cedar. Incense Cedar Transverse. Growth rings broad. The dense summer wood rather thin and composed of 8-14 tracheids, often more or less double ; the tran- -sition from the spring wood gradual. Spring tracheids in regular rows, uniform, squarish, large and thin-walled, the structure open. Resin cells numerous,, prominent, large, in a very broad band or scattering through the late spring wood. Medullary rays prominent, numerous, resinous, 1 cell wide; distant 2-8, rarely 15, rows of tracheids. Radial. Ray cells sparingly resinous, more or less contracted at the ends, equal to about 4-8 spring tracheids ; the upper and lower walls medium and entire, or again distantly and often imperfectly pitted ; the ter- minal walls thin, straight, or curved and locally thickened or even coarsely pitted ; the lateral walls with small, narrowly bordered, oval pits with a lenticular, diagonal orifice, 1-4 per tracheid. Bordered pits in I row, sometimes in pairs, numerous. Pits on the tangential walls of the summer tracheids numerous and large, extending almost through the entire zone. Resin cells 20-30 /it wide, chiefly 1 75-225 /n long, less commonly upwards of 475 /tt. Tangential. Rays very variable, often 2-3 seriate at the center or near one end, sparingly resinous, rather broad ; the cells round or oval, uniform, the walls medium. 'I I !r iir. 220 ANATOMY OF THE GYMNOSFERMS A lar^e t ^0-40 m. in height, with a trunk 1.20-2.10 m. in diameter. The ligl' ! wood is very durable in contact with the soil. Ri specific gravity 0.4017 Ai mate relative fuel value 401 4 0 -lent of elasticity, in kilograms on millimeters . . 847. Ui ate transverse strength in kilograms 291. Uiuinate resistance to longitudinal crushing in kilograms 7446. Resistance to indentation to i. 27 mm. in kilogram.s . . 1561. (Sargent) Santian river, Oregon ; southward along the western slopes of the Cas- cade and Sierra Nevada mountains at elevations of 3000-8500 feet, thence through California Coast Range to the San Bernardino and Cayu- maca mountains (Sargent). 8. • THUYA, TouRN. Plates 34 and 35 Transverse. Summer wood thin and dense. Resin passages wholly want- ing. Resin cells more or less prominent, but often widely scattering. Tracheids chiefly large and thin-walled, squarish. Radial. Ray tracheids wholly wanting except in T. japonica. Ray cellh usually conspicuously contracted at the ends ; the terminal walls thin and not pitted or locally thickened, usually much curved. Tracheids wholly without spirals. Tanj^ential. Fusiform rays wholly wanting. Ordinary rays narrow, medium to low, strictly i -seriate, the cells chiefly narrowly oval to oblong. Synop.sis of Species Pits on the lateral walls of the ray cells 1-2, or in the marginal cells and low rays upwards of 8 per tracheid. Pits on the tangential walls of the summer wood confined to the outermost wall. 3. T. japonica, Max. Pits on the lateral walls of the ray cells 1-4, or in the marginal cells and low rays 6 per tracheid. Pits on the tangential walls of the summer wood not confined to tin- outermost tracheid wall. 1. T. gigantea, Nutt. Pits on the lateral walls of the ray cells 1-4, or in the marginal cells and low rays 7 per tracheid. Pits on the tangential walls of the summer wood confined to tlit- outermost tracheid wall. 2. * T. occidentalis, Linn. THUYA 3ai 1. T. glgantM, Nutt. Rtd Ctdar. Canoe Ctdar. n'ttttrn White Cedar Transverse. Growth rings usually broad. Summer wood prominent and upwards of 14 tracheids thick, the transition to the sprinj; wood gradual. Spring wood open, the thin-walled tracheids s(|uari.sh- hexagonal, rather uniform, in regular rows. Kesin cells usually in a single narrow band in the summer wood of distant growth rings, thus often apparently wanting. Medullary rays somewhat resinou.s, i cell wide, distant 2-20 tracheids. Radial. Rays devoid of tracheids, somewhat resinous. Ray cells con- spicuously contracted at the ends ; the upper and lower walls thick- ish and entire or remotely pitted ; the terminal walls thin, generally curved, • ot pitt d or locally thickened ; the lateral walls with small, oval pits with a lenticular or oval orifice, 1-4, or in the marginal cells and low rays 0 per tracheid. Bordered pits round, in one row, sometimes in pairs. Fits on the tangential walls of the summer wood small, conspicuous, often remote, not confined to the outermo.st wall. Resin cells about 15 /t wide, 60-255 M long, very variable, thin-walled. Taiii^ential. Rays medium, narrow, the cells oblong. A light, soft, and rather brittle wood which is very durable in the soil. Relative specific gravity 0.3706 Approximate relative fuel value 37. Qo Coefficient of elasticity in kilograms on millimeters . . 1034. Ultimate transverse strength in kilograms 319. Ultimate resistance to longitudinal crushing in kilograms 7197. Resistance to indentation to 1.27 mm. in kilograms . . 1114. (Sargent) Alaska, .southward through the coast ranges of Briti.sh Columbia, where it attains to an altitude upwards of 6000 feet, often attaining a height of 150 feet and a diameter of more than 10 feet (Macoun); thence through Washington Oregon, and California, as far as Mendocino County, and eastw.u through Washington and Idaho to northern Montana (Sargent). 2. * T. occidentalis, Linn. White Cedar. Arbor yHw Transverse. Growth rings chiefly broad but variable. ummer wood very thin, of 2-6 or upwards of 14 tracheids, the stn ure very open, the tracheids large and squarish-hexagonal, in regi ir rows, rather uni- form, thin-walled. Resin cells few and widely se.ittering, often appar- ently wanting, or sometimes distantly zonate in the spring wood. Medullary- rays not prominent, i cell wide, distant 2-15 tracheids. Radial. P lys devoid of tracheids, sparingly, if at all, resinous. Ray cells more or less contracted at the ends; the upper and lower walls medium, with conspicuous though often distant pits; the terminal walls thin, often strongly curved, not pitted or locally thickened; t m 1 ^^^t,_ 323 ANAl'OMY OF THE GYMwOSPERMS the upper and lower walls medium, with conxpicunu.s, though often distant, simple pits; the lateral walls with small, oval pitH with in oval or lenticular, rather large, orifice, 1-4, or in the marginal cells and low rays 7 per tracheid. Bordered pits elliptical in one row, some- times in pairs, those of the summer wood tinally obscure and wanting. Pits on the tangential walls of the summer wood small, often obscure, freque :Iy very distant and confined to the outermost tracheid wall. Resin cells 15-40 /t wide. Tangential. Rays low and narrow, the cells uniformly narrow, oblong. A tree 13-18 m. in heig^-t and 1.20-1.50 m. in diameter, producing a light, soft, and very durable wood. Relative specific gravity 0.3164 Approximate relative fuel value 31-53 Coefficient of elasticity in kilograms on millimeters . . 533. Ultimate transverse strength in kilograms 219. Ultimate resistance to longitudinal crushing in kilograms 4903. Resistance to indentation to 1.27 mm. in kilograms . . 957. (Sargent) Rare in Nova Scotia ; abundant in New Brunswick, Quebec, and Ontario, and northward to Hudson's Bay ; westward to Lake Winnipeg and tho mouth of the Saskatchewan in latitude 53" 30' N. (Macoun); southward to New Jersey and through the Alleghenies to North Carolina (Britton) ; thence westward through New York and Pennsylvania to central Michi gan, no- 'hem Illinois, and central Minnesota (Sargent). This sjjec' • :s a well-defined and .somewhat abundant constituent of the Pleistocene flora in the Uon Valley at Toronto, and the Leda clays of Montreal ; Leda River, Manitoba, and Marietta, Ohio. An undescrilxd species of Thuya also occurs in the Mgnite Tertiary, Saskatchewan, probably of the Porcupine Creek and Great Valley groups. 3. T. japonica, Max. Jap. — Xedzuko Transverse. Growth rings rather narrow, variable ; the prominent summer wood very narrow, of about 6 tracheids, or again upwards of 16 tra- cheids, rather dense, the transition to the spring wood gradual. The broad spring wood open ; the tracheids rather large, con.spicuously hexagonal, very thin-walled, in regular rows, uniform. Resin cells prominent and dark, few and widely scattering, chiefly in the summer wood. Medullary rays not prominent, sparingly resinous i cell wide, narrow, distant 2-18 tracheids. Radial. Rays very sparingly resinous, rarely with tracheids. Cells chiefly straight, the upper and lower walls rather thin, uniform, and fre- quently pitted ; the terminal walls thin, very commonly curved, not SKQUOIA 223 pitted or locally thickened: the lateral walU with small, oval piu, the orilicc broadly ItiitiLular, 12 or in the ni.iri;inal cells and low rays upwards of « per tracheid. Bordered pits illiptical in one row, sometimes in pairs, numerous, alx>ut one half the diameter of the tracheid. Fits on the tangential walls of the summer wi"hI confined to 'he outermost wall, not lar^e, flat, rather numerous, often obscure. Kesin cells few, 12.5/1 wide, al)aut 135 /t lon^. TaHj^ential. Hays low to medium, very narrow, strictly i-seriate ; the cells uniform Jiin-walled, obloi.,,. 9. • SEQUOIA, Endi.. Plates 36 and 37 Transverse. Growth rings chiefly narrow, the usually thin summer w(mxI distinct. Resin cysts when present forming a continuous row on thf; outer face of distant growth rings. Tracheids large, thin-walled, square. Resin cells scattering, chiefly in the spring wood, or more rarely wholly in the summer wood (S. Penhallowii), Radial. Rays without tracheids, but the marginal cells .sometinus crystal- logenous (S. Penhallowii). Pits of the ray cells with a narrow border, the orifice commonly parallel with the cell axis. Pits ofton occur on the tangential walls of both spring and summer tracheid.*. Terminal walls of the ray cells rarely, if at all, oitted, except in S. I •.■nhallowii. Tracheids wholly without spirals. i{. Bordered pit.s in i-j rows. Ray cells (tangential) very larjje and firoatf, squarish. Pits on the lateral walls of the ray cells 2-6 per tracheid. I. S. sempervirens. Ray cells (tanKential) ov.il or round. Pits on the lateral walls of the ray cells obliterated. 3. • • S. Langsdorfii. Resin passages (radial only) with thyloses. Resin cells somewhat numerous, scattering throughout the growth ring but most abundant on the outer face of the summer wood. Bordered pits in 1-2 rows. Marginal ray cells not crystallogenous. 4. • • S. Burgessii. Resin passages (traumatic) present, both vertically and radially. Resin cells on the outer face of the summer wood only. Bordered pits not definitely .seriate. Pits on the lateral walls of the ray cells 1 -seriate in the central, 2-3 seriate in the marginal cells which are crystal- logenous. 6. • • S. Penhallowii. 1. S. cempenrirens, EnUI. KtdwooJ Transverse. Summer wood very prominent, of 3-1 1 tracheids, or upwards of one third the spring wood ; the structure ofte'i -.ery open, or whtn dense soinetimes double. Spring wood very open, the large, squarish, or hexagonal tracheids often radially elongated, the walls thin ; tran- sition to the summer wood rather abrupt. Resin cysts contiguous and coalescent and forming an extended tangential series in the mitial growth of the spring wood, of distant growth rings. Kcsin cells rather abundant, very prominent and dark, rather large, scattir ing through the spring \\,>od. Tracheids rather uniform in viry irregular rows. Medullary rays broad, prominent, 1 cell wide, distant I -1 2, more rarely 20, rows of tracheids. SEQUOIA "5 RMlml Kay celU utraiKht or rarely contacted at the cmls. somewhal resnouH, equal to alwut 4 "prinK tracht,tl»; the upper and lower wall!, thin, rather uniform, rarely pittciJ ; the terminal walls vtry thin. utralKht or curved, and not pitted; the lateral walln with lartre oval naiTowly bordered pits. 2-6 per tracheid, the round or hro.uUy oMonJ orifice either parallel with or diaRonal to thi- cell axis. Bordered uiln con»picuou.sly in 1-2 row». elliptical. I'itn on the lanKential walU of the Hummer \».K)d numerous, small, the orifice l.roadly trumiH.t-.Hhapid or bell-Hhaped ; the pits on the tanKcntial walls of the sprinir wood large, sometimes rather abundant. Resin cell, rather numerous 30-40 ^ wide, 1 75-480 /t long. TaHf^eufial. Rays medium to high, often more or less 2-seriate • the cells very lar^e and broadly oval, tho.se in the center commonly'conspicu- ously squarish. ' ^ Wood very durable in contact with the soil and of Kre.U economic value Trees 61-92 m. in height and 2.40-7 m. in diameter. Relative specific gravity Approximate relative fuel value ........' Coefficient of elasticity in kilograms on millimeters '. Ultimate transverse strength in kilograms Ultimate resistance to longitudinal crushing in kilograms Resistance to indentation to 1.27 mm. in kilograms (Sargent) 0.4208 42.02 676. 25s. 1242. From the northern borders of California southward through the coast ranges to near the southern boundary of Monterey County (Sargent). 2. S. gigaatea, Decaisne Big Trtt Transverse. Summer wood very thin, of 2-6 tracheids, the transition to the spring wood usually abrupt. Spring tracheids large, open, thin- walled, uniform, squarish, in regular row s. Resin cells not vcrv numer- ous, but laige ana prominent, scattering. Medullary rays not very prominent, rather numerous, 1 cell wide; distant 2-14', rarely ->c rows of tracheids. •' "^' Kadial. y.a.y cells usually .Mjmewhat contracted at the ends, equal to 6-8 •spring tracheids, i hiefly resinous throughout ; the upper and lower walls thin and entire or distantly pitted, unequal ; the terminal walls thin, straight or curved, not pitted or locally thickened ; the lateral walls with oval and commonly narrowly bordered pits, the broadly oblong oritice equal to the outer limits of the pit nnd chiefly parallel to the cell axis, 1^2, or more rarely 3-4, per tracheid. Bordered pits in one or two row.s, elliptical, the orifice large, elliptical. Fits on the tangential walls of the summer wood prominent and frequent; on the tangential walls of the spring wood prominent but rare. Resin cells few, about 20 ^ wide and 140-325 n long, chiefly about 250 u. Jangettiial. Rays chiefly low to medium, the large cells broadly oval or round, thin-walled. 226 ANATOMY OF THE GYMNOSPERMS IH A light, soft wood remarkable for its durability in the soil. The tree is the lar;;est produced by American forests, attaining a height of 79-119 m. and a diameter of 6-1 1 m. Relative specific gravity 0.2882 Approximate relative fuel value 28.67 Coefficient of elasticity in kilograms on millimeters . . 451. Ultimate transverse strength in kilograms 196. Ultimate resistance to longitudinal crushing in kilograms 6210. Resistance to indentation to 1.27 mm. in kilograms . . 1091, (Sargent) Western slopes of the Sierra Nevada Mountains, California, from Placer County south to Deer Creek on the southern borders of Tulare County (Sargent). 3. * * S. Langsdoifii (Brongn), Heer. Transi'trse. Growth rings medium, strongly defined. Tracheids of the spring wood squarish, large, S2x 52 ^ the walls 14 fi thick. Summer wood of 3-6 tracheids in thickness, the transition from the spring wood rather abrupt. Hesin cells rather numerous throughout the growth ring and scattering. Resin passages usually absent, but occu- sionally appearing in a rudimentary form on the outer face of the summer wood. Radial. Medullary rays devoid of tracheids ; the parenchyma cells equal to about 4 tracheids, somewhat constricted at the ends ; the upper and lower walls thin and entire ; the terminal walls not pitted, straight or curved ; the lateral walls with no recognizable structural details. Tangential. Medullary rays i -seriate or rarely 2-seriate in part, the oval or round cells about 31.5/11 broad. This very widely distributed and well-known Cretaceous and Tertiary plant, which is chiefly represented by foliage and fruit, is apparently repre- sented also by the woody stem in the Lignite Tertiary of the Porcupine Creek and Great Valley groups in Saskatchewan. Reference of the wood to this species is, however, made provisionally, as the evidence is not such as to warrant an absolute decision. The occurrence of the genus in this locality, however, indicates that it at one time occupied the present prairie region in preglacial times, and that its recession to its present narrow limits probably occurred as the result of glacial action. 4. • • S. Burgessii, Penh. Transverse. Growth rings chiefly narrow but variable, the rather narrow- but variable summer wood dense, the transition from the spring wood abrupt. Tracheids of the spring wood large, squarish, and thin-walled. Resin canals wholly wanting. Resin cells numerous throughout the growth ring, but especially on the outer face of the summer wood : with dark, massive resin. Medullary rays chiefly I cell wide, occa- sionally broader and bearing a resin canal with large thyloses. SEQUOIA 227 Radial. Bordered pits large, in 1-2 rows. Medullary rays often with a large resin passage bearing thyloses; the cells all of one kind; the upper and lower walls thin and much altered by decay ; the lateral walls devoid of recognizable markings. Tangentiai. Ordinary rays i- or sometimes 2-seriate in part; the fusiform rays with large resin passages containing thyloses. An exceedingly well-characterized species from the Eocene of the Porcu- pine Creek and Great Valley groups. 5. * • S. magniflca, Knowlton "Trunks often of great size, 6-10 feet in diameter, 30 feet high as now preserved, bark when present 5 or 6 inches in thickness ; annual rings very distinct, 2-3 mm. broad." " Transverse. In this section the structure appears beautifully preserved. The rings are rather narrow, being only 2 or 3 mm. broad, or often only 1 mm. They are very sharply demarked, even to the naked eye. Under the microscope the rings are found to consist of a band of thick-walled cells that is never more than 1 5 rows of cells deep and often reduced to 2 or 3 rows. The cells composing the spring and summer wood are of uniform size and inclined to hexagonal in shape. Those of the fall wood are, of course, compressed. " The resin cells are numerous and may be readily distinguished by the dark contents. They occur mainly in the spring and summer wood. " The medullary rays seen in this section are long, straight, and separated by usually about 3 rows of wood cells." "Radial. This section is the least satisfactory of all. The wood cells show well under the microscope, but their markings are very obscure. By prolonged search it is made out that the pits are in i row, or some- times 2 parallel rows. They are small, as far as can be made out, and are too obscure for satisfactory measurement. " The rays are composed of long, unmarked cells." " Tangential. This section is very satisfactory. The wood cells are long and unmarked. The resin ducts are numerous, but scattered, the cells being twice or three times as long as wide. In many ca.ses they are filled with or contain masses of dark material, rcpre.senting the resin now turned to a carbonaceous mass. "The medullary rays are compo.sed of 1, or in some cases of a partially double, series of 2 to about 25 superimpcsed cells. They are large and quite thick-walled. The average number of cells in each ray is about 12" (Knowlton). According to Professor F. H. Knowlton, this species can hardly be dis- tinguished from the existing S. sempervirens, of which he considers it to be the ancestral form. Tertiary of the Yellowstone National Park, at Specimen Ridge, Fossil Forest at head of Crystal Creek, Fossil Forest on Cache Creek, etc. (Knowlton). 328 ANATOMY OF THE GYMNOSPERMS 6. * • S. Pentaallowii, JefiFtey " Tranmerse. Rings of growth rather narrow, with sharply marked but thin summer wood. Rings regular, or if varying in thickness, varying uni- formly and without violent transitions except as the result of injury. Resin canals present in both the vertical and horizontal planes appar- ently only as the result of injury. The resin canals when present surrounded by resin cells, containing dark brown resin. Resin cells inconspicuous and confined to the face of the summer wood, except in the case of injury, where they may be present throughout the zone of annual growth. Tracheids of the spring wood very large and with pits on the radial walls only. T.acheids of the summer wood with tangential pits." " Radial. Rays without tracheidal cells, but with distinctly differentiated marginal cells. Lateral pits of the ray cells elliptical, bordered, larger in the marginal cells. Rows of pits single in the central cells of the ray and 2-3 seriate in the marginal cells. Medullary ray cells covering 1-4 tracheids, the central ones resiniferous, the marginal generally empty, sometimes containing large clinorhombic crystals inclosed in cysts derived from the cell walls. Marginal cells with undulating free border, deeper than central cells. End walls of the cells of the medul- lary rays very strongly pitted. Longitudinal walls of ray cells also pitted and rather thick. Rays contain resin canals in the case of injury, which take their origin from similar vertical canals running in the wood. Resin canals of the rays sometimes ending blindly and sometimes in a more external series of vertical canals, often extending through many annual rings, varying greatly in size and frequently occluded by thyloses. Spring tracheids generally with 2 rows of oppo- site pits, which often alternate in the ends." " Tangential. Rays of one kind only in uninjured parts of the wood. Fusi- form rays present with linear rays in the case of injury and varying greatly in size. Fusiform rays, when present, generally with central resin canal, which is often occluded by thyloses. Linear rays varying greatly in depth. No pits on the tangential walls of the spring tra- cheids. Pits on the tangential walls of the summer tracheids numer- ous, generally not in rows " (Jeffrey). Material but slightly silicified and showing little alteration through decay. From a waterwom fragment of a trunk originally 6 feet or more in diameter. Miocene(i'), trom Tunnel No. 1, Central Pacific Railway, at Blue Gap, Sierra Nevada Mountains (Jeffrey). 10. • CUPRESSUS, TouRN. Plates 38 and 39 Transverse. Summer wood usually very thin, often barely distinguishable, the structure of the growth ring open throughout. Resin passages wholly wanting. Resin cells prominent, rather numerous in bands, scattering or even apparently wanting. CUPRESSUS fig Radial. Kays chiefly without tracheids. Terminal walls of the ray cells thin and entire, very commonly cu— cd, often locally thickened. Tracheids wholly without spirals. Tangential. Fusiform rays wholly wanting. Ray cell.s chiefly broad, oval, or even transversely oval ; the rays sometimes 2-seriate in part. Synopsis of Species A. * CHAMi€CYPARIS Existing S/iecies I. Pits on the tangential walls of the summer tracheids flat, small, obscure, or at least not prominent Ray cells (tangential) round or oval. Ray tracheids absent. Tracheids more or less conspicuously rounded throughout. Ray cells (radial) straight, sparingly resinous. Pits on the lateral walls of the ray cells 2, in radial series, or in the marginal cells 6, per tracheid. 5. C. obtusa. Tracheids distinctly squarish, large, the structure open. Pits on the lateral walls of the ray cells 2-4, rarely 8, per tracheid. 2. C. Lawsoniana. Pits on the lateral walls of the ray cells 2, in radial series, or 6, per tracheid. 3. C. pisifera. Ray tracheids present in the low rays. Tracheids distinctly squarish, or again rounded and thick-walled, the structure variable, either open or somewhat dense. Pits on the lateral walls of the ray cells 1-4 per tracheid. Tracheids (transverse) commonly in very irregular rows. 4. C. nootkatensis. Ray < ells (tangential) narrow, oblong, more rarely oval. Tracheids distinctly squarish, in regular rows, the structure open. Pits on the lateral walls of the ray cells 1-2, or in the marginal cells and low rays upwards of C, per tracheid. I. C. thyoides. B. CUPRESSUS Existing Species 2. Pits on the tangential walls of the summer tracheids chiefly large and open Ray cells (tangential) round or oval, more rarely transversely oval. 230 ANATOMY OF THE GYMNOSPERMS Tracheids more or less conspicuously rounded throughout. Ray cells (radial) somewhat contracted at the ends, strongly resinous. Pits on the lateral walls of the ray cells 1-2, rarely 4, per tracheid. 6. C. macrocarpa. Tracheids barely if at all rounded. Ray cells (radial) contracted at the ends, more or less resinous. Pits on the lateral walls of the ray cells 1-2, rarely 3, per tracheid. 8. C. Macnabiana. Ray cells (tangential) chiefly transversely oval. Tracheids more or less rounded throughout. Ray cells (radial) somewhat contracted at the ends, barely resinous. Pits on the lateral walls of the ray cells 1-2, more rarely 4, per tracheid. 7. C. arizonica. Tracheids squarish, the structure open throughout. Ray cells (radial) strongly fusiform, generally resinous. Pits on the lateral walls of the ray cells 1-2 per tracheid. 9. C. Goveniana. C. * • CUPRESSOXYLON (Cupressinoxylon) Extinct Species Tracheids of the spring wood distinctly rounded. Bordered pits obliterated by dtcay. Medullary rays (tangential) 1-3 .seriate, the round, thin-walled cells 47 n broad. 10. C. cheyennense. Bordered pits in i row, distant, round. Pits on the lateral walls of the ray cells 1-2, chiefly 2, per tracheid. Rays (tangential) numerous, the variable cells chiefly broad, oval, or round, metimes transversely oval. 1 1 . C, macrocarpoides. Bordered pits large, in 1 row, or often in pairs, and in larger tracheids becoming more or less 2-rowed. Pits on the lateral walls of the ray cells 1-2 per tracheid. Medullary rays (tangential) i-seriate, the round cells 19 n broad. 12. C. comanchense. CUFB^'iSUS 231 Tracheids of the spring wood squansh hexagonal. Bordered piis round, distant, in 1 row. 13. C. pulchellum. 14. C. arkansanum. Bordertd pits large, in i row, often i . pairs, the latter sometimes so approximated as to make the pits more or less 2-rowed. Pits on the lateral walls of the ray cells 1-2, in vertical series, or in marginal cells and low rays 4, per tracheid. 15. C. Dawsoni. Pits on the lateral walls of the ray cells obliterated. 16. C. Wardi. Pits on the lateral walls of the ray cells minute, round. Medullary rays (tangential) small, the cells small, oblong, 1S-17X 10 (t,. 17. C. columbianum. Bordered pits conspicuously in 2 rows. Pits on the lateral walls of the ray cells obliterated. Growth rings obscure. 18. C. elongatum. Growth rings sharply defined. Tracheids of the earlier spring wood very large and thin-walled. 19. C. glasgowi. Bordered pits in 2, or sometimes 3, rows. Pits on the lateral walls of the ray cells with large, oval pits 1-3 per tracheid. 20. C. McGeei. Pits on the lateral walls of the ray cells 3 per tracheid. 21. C. Calli. A. CHAM/ECYPARIS 1. * C. thyoides, Linn. fVAitt Cedar Trans7'erse. Growth rings thin, variable, the structure open throughout. The summer wood chiefly thin, of 2-6 tracheids, the transition to the spring wood rather abrupt, or sometimes thicker and not clearly sepa- rable from the spring wood. Spring tracheids lar^e, conspicuously squarish, uniform, in regular rows, in small stems and branches often much elongated radially, the walls not very thin. Resin ceils widely scattering and often apparently wanting ; when in bands, often giving the appearance of secondary growth rings, chiefly in or near the sum- mer wood. Medullary rays not very prominent or resinous, i cell wide, distant 2-12 tracheids. 232 ANATOMY OF THE GYMNOSPERMS Radial. Ray tracheids chiefly narrow, very unequal, often high, sometimes present, then rather abundant and composing the enti ray when of 1 or 2 cells only, usually absent from the higher rays. Medullary rays contracted at the ends; the upper and lower walls medium to thick, unequal, frequently pitted or again entire or distantly pitted ; the terminal walls thin, often curved and locally thickened ; the lateral walls with round or oval pits, the orifice lenticular, 1-2, or in the marginal cells and low rays, 6, per tracheid. Pits on the tangential walls of the summer tracheids very small and often obscure. Bor- dered pits round or elliptical in 1 row, or in radially broad tracheids in 2 rows. Kesin cells not numerous, 20-25 y, wide, 150-175 u long. Tangential. Rays medium, wholly i-seriate ; the cells narrow, oblong. Wood very light and soft, but very durable in the soil. Relative specific gravity 0.3322 Approximate relative fuel value 33.12' Coefficient of elasticity in kilograms on millimeters . . 404. Ultimate transverse strength in kilograms 194. Ultimate resistance to longitudinal crushing in kilograms 4149. Resistance to indentation to 1.27 mm. in kilograms . . 1074. (Sargent) Cape Breton Island and near Halifax (Macoun) ; southern Maine, south- ward along the coast to Florida, thence westward along the Gulf coast to Pearl River, Mississippi (Sargent). The Pleistocene deposits of the Don Valley, Toronto. Material not pet- rified, but often showing the effects of advanced decay. 2. C. Lawsonijuu, A. Murr. Port Orford Cedar. Oregon Cedar. White Cedar. Lawson's Cypress. Ginger Pine Transverse. Growth rings very narrow, variable, the structure very open throughout. Summer wood very thin, of 1-5 tracheids, sometimes double and then upwards of 14 tracheids, the transition to the spring wood gradual. Spring tracheids very large, squarish-hexagonal, thin- walled, in very regular rows, uniform. Resin cells prominent, large, usually widely scattering and not numerous, or again numerous within narrow zones in the summer wood. Medullary rays resinous, rather prominent and numerous, i cell wide, distant 1-9 or 12 tracheids. Radial. Ray tracheids wholly wanting. The straight or somewhat con- tracted ray cells rather resinous, equal to 3-12 spring tracheids; the upper and lower walls variablj, often strongly thickened toward the ends of the cells, not obviously pitted; the terminal walls thickish, chiefly straight, not pitted or locally thickened ; the lateral walls with small bordered pits with a narrow orifice, 1-4, or more rarely upwards of 8, per tracheid and chiefly in vertical rows. Bordered pits in 1 row, sometimes in 2 rows, round. Pits on the tangential walls of the CUPRESSUS 233 summer tracheids small, rarely large, not numerous. Resin cells not numerous, 20-25 M wide, 150-200 /i long, chiefly about 175 ^. Tangenlial. Rays medium, wholly i-scriate; the cells broadly oblong or oval, sometimes round, the walls thick. A light, hard, and strong wood which is very durable in the soil. Relative specific gravity 0.4621 Approximate relative fuel value 46.16 Coefficient of elasticity in kilograms on millimeters . . 1217. Ultimate transverse strength in kilograms 370. Ultimate resistance to longitudinal crushing in kilograms 7435. Resistance to indentation to 1.27 mm. in kilograms 131 7 (Sargent) Oregon, not more than thirty miles from the coast ; valley of the upper Sacramento River, California (Sargent). 3. C. pUifera, Sieb. et Zucc. /af. = Saviara Trans-verse, Growth rings narrow, uniform ; the usually dense and very narrow summer wood of 3-5 tracheids, the transition to the spring wood somewhat abrupt ; the spring wood open, the large, squarish- hexagonal f'acheids in very regular rows, uniform, rather thin-walled. Resin cells few, dark, and prominent, zonate in the summer wood. Medullary rays not prominent, I cell wide, narrow, distant 2-17 tracheids. Radial. Rays devoid of tracheids, nonresinous, the cells contracted at the ends, equ?" -.0 5-6 spring tracheids ; the upper and lower walls thin, rather u. qual, not obviously pitted; the terminal walls thin, chiefly curved, not pitted or locally thickened ; the lateral walls with oval, bordered pits, chiefly 2 per tracheid in radial series, or in the marginal ceils and low rays smaller and upwards of 6 per tracheid. Bordered pits elliptical, large, rather numerous in i row or sometimes in pairs. Pits on the tangential walls of the summer tracheids rather few, small, flat, and inconspicuous. Resin cells few in the summer wood, 12.5-20 /* wide, 170-250 // long. Tangential. Rays low to medium, narrow, nonresinous ; the cells rather variable from oblong to oval or round, chiefly rather oblong, rarely if ever in pairs. 4. C. nootkatcnsis. Lam. Yellmv Cypress. Sitka Cypress Trans7>erse. Growth rings unequal. Summer wood very thin, of 2-6 tracheids, the transition to the spring wood gradual. Spring tracheids chiefly large, but very variable and often in irregular rows, squarish Resin cells prominent and ra'ier numerous, either scattering or com- pressed into narrow bands in both the spring and summer wood. Medullary rays resinous, prominent, i cell wide, distant about 2-17 tracheids. it. 234 ANATOMY OF THK GYMXOSPERMS Raiiial. Ray trarlicids chiefly short and broad : chiefly or wholly confined lo rays r or 2 cells hi);h, then constituting the en'ire ray, not very numerous. Kay cells somewhat resinous, more o' less conspicuously contracted at the ends, equal to 4-9 sprinj; trachoids ; the upper and lower walls thick and entire or distantly pitted; the terminal walls thin and locally thickened ; the lateral walls with rather small pits with a lenticular orifice often parallel with the cell axis, 1-4 per tracheid. Bordered pits round or elliptical in I row, somewhat distant ; the round orifice often very variable, much enlarged, eccentric, irregular in outline or even wanting, the pits then presenting a vari- able aspect which at once ser%es to define the species. Pits on the tan- gential walls of the summer tracheids few, often ob.scure. Resin cells few, about 20 /i wide and 100-175 ^ long, rarely upwards of 270 /*. Tatttreniial. Rays low, narrow, and i -seriate, sometimes 2-seriate in part; the cells narrowly elliptical or broadly oval, sometimes transversely oval or oblong, much enlarged. This is the most variable .species of Cupressus, and it is chiefly remarkable for the variable character of the summer wood, the irregular disposition of the tracheids (transverse), the often very numerous resin cells, and the peculiarly imperfect bordered pits which at once separate it from all other species. It may show deviation from the normal in (i) the absence of resin cells ; (2) the form of the tracheids, which are some- times round with thick walls, even in the same section, thus giving rise to (3) a variable structure of the wood which is in some rings rather dense throughout. A large tree of great economic importance with a height of 30-38 m. and a diameter of 1.20-1.80 m. Wood light, hard, and very durable. Relative specific gravity 0.4782 Approximate relative fuel valu^ 47.66 Coefficient of elasticity in kilogram. . n millimeters . . 1029. Ultimate transverse strength in kilograms 342. Ultimate resistance to longitudinal crushing in kilograms 7281. Resistance to indentation to 1.27 mm. in kilograms . . 161 8. (Sargent) Interior of Vancouver Lsland ; British Columbia, near the coast, where it reaches sea level in the northern portion.s, and thence to Alaska (Macoun) ; southward through the Cascade Mountains of Washington and Oregon, where it is seldom found below an elevation of 5000 feet (Sargent). 5. C. obtusa, Sieb. et Zucc. Jap. = Hinoki Transverse. Growth rings broad. Summer wood chiefly rather thin, some- times double, rather open but passing very gradually into the broad spring wood from which it is not clearly separable. Tracheids of the spring wood round-hexagonal, thickish-walled, not very large, the v CUPRESSUS ^35 utructure not very open. Resin cells prominent, dark, not very large or numerous, rather sratterinj,' or again zonate in both spring and summer woods. Medullary rays not prominent or numerou.s, rather narrow and i tell wide, distant 1-23 fracheids. Kadial. Medullary rays devoid of tracheids, sparingly resinous, the cells straight and equal to 5-10 spring tracheids; the upper and lower wa s thickish, sinuately unequal, not obviously pitted ; the terminal walls thin, curved or straight, not pitted or locally thickened; the lateral walls with oval, bo^ered pits, chiefly i, or in the marginal cells 2, per tracheid, the orifice lenticular-oblong. Bordered pits round or elliptical, rather distant in 1 row, usually less than one half the diameter of the tracheid. Pits on the tangential walls of the summer tracheids not very numerous, small, flat, obscure. Resin cells few, 15-25 fi. wide, 150-210 /t long, chiefly about 150 /*. Tangential. ays medium, narrow; the uniformly oval, nonresinous cells rarely if ever in pairs. B. CUPRESSUS 6. C. macrocupa, Gordon Monterty Cyprus Trans-verse. Growth rings usually broad. Summer wood very thin, of 6-8 tracheids, and passing gradually into the spring wood from which it is not always clearly .separable. Spring wood very broad, the tra- cheids unifcrm, rather large, rounded-hexagonal, the walls rather thick. Resin cells prominent and widely scattering or somewl... zonate in the summer wood. Medullary rays prominent, resinous, broad. 1 cell wide, distant 2-12, rarely 33, tracheids. Kadial. Rays devoid of tracheids and resinous throughout. Cells more or less contracted at the ends, equal to 4-6 spring tracheids ; the upper and lower walls variable and not obviously pitted ; the ter.T.inal walls thin, often curved, locally thickened ; the lateral walls with rather large bordered pits with large, lenticular, or oblong orifices, 1-2, or in the low rays 4, per tracheid. Bordered pits round or elliptical, some- times in pairs. Pits on the tangential walls of the summer tracheids numerous, large, and open. Resin cells not numerou.s, 20-25 M wide, 40-65 /bt long, chiefly about 50 /i. Tangential. Rays medium, sometimes 2-seriate in part, the cells broadly often transversely oval, thick-walled. This species is usually recognized by the very large, bordered pits on the tangential walls of the summer tracheids. In transverse section the summer wood commonly presents somewhat strong variations in speci- mens from different individuals. Wood heavy, hard, strong, and very durable. Trees upward of 21 m in height and i .80 m. in diameter. Relative specific gravity (Sargent) California (Sargent). 0.6261 if a^ ANATOMY OF THE (lYMNOSPERMS 7. C. arlMnk*, Cireene I'yfrtss Transvtrst. Growth rings medium, rather uniform. Summer wood very thin, upwards of 6 tracheir* and passing very gradually into the spring wood. The very broad spring wood somewliat open, the very variable tracheids chiefly squarish-hexagonal, the walls not thin. Kesin cells numerous and prominent, narrowly zonate in both the spring and summer woods, sometimes in groups of larger and thicker- walled cells, showing a tendency to the formation of resin canal.s. Medullary ray.s rather prominent, somewhat resinous, rather numerouii and broad, i cell wide, distant 2-10 tracheids. Radial. Rays devoid of tracheids and sparingly resinous, the cells con- spicuously contracted at the ends, equal to about 6-9 spring tracheid.s ; the terminal walls chiefly straight, sparingly and locally thickened ; the upper and lower walls medium to thick, not obviously pitted ; the lat- eral walls with round or oval pits 1-2, or in the marginal cells 4, per tracheid. Bordered pits round or elliptical, rather numerous, in 1 row. Pits on the tangential walls of the summer tracheids rather numer- ous and large, open. Kesin cells not numerous, 1 5-20 ^ wide, 1 20- 250 ^lon§, chiefly about 200/1; sometimes in multiple .sei'es of much broader, very variable, often isodiametric and thick-walled cells, show- ing a strong tendency to the formation of resin canals. Tangential. Kays medium, the cells broad, more or less resinous, trans- versely oval, or in the low rays vertically oval. Wood soft, light, and coarse grained. Kelative specific gravity (Sargent) 0.4843 San Francisco Mountains of New Mexico and Arizona, where the tree forms extensive forests on the northern slopes of the mountains at eleva- tions of 5000-8000 feet ; Santa Catalina and Santa Kita mountain.s of Arizona ; on the Sierra Madre and Guadeloupe Islan 1 Mexico (Sargent). 8. C. Macnabiana, A. Murr. Cypress Transverse. Growth rings medium, uniform. Summer wood very thin, of about 3-5 tracheids, open, the transition to the spring wood gradual. The L.road spring wood rather open, the tracheids conspicuously he,\- agonal, rather uniform, the walls medium. Resin cells prominent, not numerous, widely scattering throughout the growth ring. Medullary rays prominent, somewhat resinous, i cell wide, distant i-io, rarely 14, tracheids. Jiadial. Kays wholly devoid of tracheids, more or less resinous throughout, im idual cells often strongly so. The cells somewhat contracted at thi, inds, equal to 4-5 spring tracheids ; the upper and lower walls medium, unequal, entire, or sparingly pitted ; the terminal walls thin and CUPRESSUS 237 chiefly straiKht, locally thickened ; the lateral walls with oval or round hr iered pits, orifice lenticular, 1-2, or in the marginal cells rarely 3, per tracheid. Bordered pits rather numerous in 1 row, elliptical, the orifice large. Pits on the tangential walls of the summer trachuds rather numerous and large, the orifice bell-shaped, not very open. Resin cells not numerous, 12.5-25 or sometimes 35 fi broad, 210- 310 n long, chiefly about 250 fi. TanKtHtial. Rays low, the cells broad, oval, or round, often resinous. A small tree of the mountains of Lake County, California (Sargent). 9. C. QoreniMU, Gordon Cyprtss Transverse. Growth rings variable. Summer wood very thin, of 2-6 tracheids; the transition to the spring wood gradual. Spring wood very open, the tracheids large and squarish, in regular rows, rather uniform and thin-walled. Resin cells abundant and prominent, in narrow but well-defined zones, sometimes forming rather extended radial .serie-s, 1 to 3 cells wide, of broader and thicker-walled cells. Medullary rays rather numerous but not very resinous or prominent, I cell wide, distant 2-8, rarely 15, tracheids. Radial. Rays devoid of tracheids, more or less resinous. Ray cells con- spicuously narrower at the ends, equal to 3-8 .sprinj; tracheids, becom- ing shorter in the summer wood ; the upper and lower walls medium, entire or distanUy pitted ; the terminal walls thin, often locally thick- ened : the lateral walls with round or oval pits having large, round or oval openings, 1-2, or in the marginal cells 4, per tracheid. Bordered pits elliptical, sometimes round in I row, becoming much more dis- tant and smaller toward the summer wood. Fits on the tangential walls of the summer tracheids rather numerous, prominent, chieHy large and open. Resin cells rather abundant, 10-20 ;x wide, 185-375 /x long, chiefly about 225 fi; sometimes in radially wide, multiple .series of broad and short, thick-walled cells. Tanf^ential. Rays low and broad, sometimes 2-seriate in part; the cells thick-walled, chiefly transversely oval. This species is largely distinguished by the smaller pits on the lateral walls of the strongly contracted ray cells, and by the transversely oval ray cells as shown in tangential section. A small tree ftirnishing a light, soft wood. Relative specific gravity 0.4689 Approximate relative fuel value 46.68 Coefficient of elasticity in kilograms on millimeters . . 499. Ultimate transverse strength in kilograms 230. Ultimate resistance to longitudinal crashing in kilograms 5742. Resistance to indentation to 1.27 mm. in kilograms . . 2852. (Sargent) Humboldt County. California, south along the coast, and through the coast ranges into southern California (Sargent). 238 ANATOMY OF THE OYMNOSPERMS I 5 I I C. *« CUPRESSOXYLON (CuprtMinoxytoo) ExIintI Sftcits Only 10. • * C. dwytnaeiiM, Penh. Tra$uvtne. W , leid* in regular, radial rows, rather uniform, roundish, about 6:-- ^ broad; the walls 15.5 ^ thiclc. Resin passai{e» and aper ' i ells wanting. Growth rings apparent, very broad; ma nditi .xtent of 20 mm., 3 growth rings of an equal thicknesx of ic ni i> "c F) esented. The tummer wood conspicuous, ahmut 3-4 cellx .< , t' tracheids about 29 x 38 ^ broad, the tani^ential wall.s at'. I ,.r /I . ick. Radial. I'tay cr . s ;»' of one kind, straight ; the upper ■■■ A lower walls thin anu to» n ' the terminal walls thin and not pitted, strait'^t or Cttrvi'J ir ! 1^ ml wftlls showing no structure which has been oblit cnte.' .w , tracheids long. TaMgeit it. K.iys %i\x, •■.•■i.<», .nedium, 1-3 seriate; tht cells, round, thin- w i>,i ', 7 (II |jn.vi. Material h icificd. './(.' Imens represented by small portions of stem. From the C .eyenni. Frnuition (Comanche Cretaceous), east of Stokes Hill, Kiowa I nd tiaker Coun'y line, Kansas (Frosser). 11. * * C. nucrocarpoldet, Penh. Transverse. (Jrowth rings rather broad. Tracheids of the spring wood round but thin-walled through the obvious effects of decay ; ratlirr uniform in regular rows, and pas.sing gradually into the rather thin but conspicuous summer wood. Resin pa-ssages wholly wanting. Resin cells not recognizable. Medullary rays prominent, often 2 cells wide, distant 1-6 rows uf tracheids. Radial. Medullary rays wholly devoid of tracheids. Ray cells more or kss conspicuously contracted at the ends, equal to about 6 spring tratlu ids; the upper and lower walls rather thin and sparingly pitted ; the tt-rmi- nal walls chiefly straight, sometimes curved, not pitted or obviously thickened locally ; the lateral walls with oval or round i^its, 1-2, chittiy 2, per tracheid. Bordered pits in i row, chiefly distant, round. 1 s on the tangential walls of the summer wood not recognizable. Ri- m cells present on the outer face of the summer wood (?), 30 « wide . id 12s /tlong. Tangential. Fusiform rays wholly wanting. Ordinary rays numerous, low to high, often more or less 2-seriate, rarely 3-seriate in part ; the n Hs variable, chiefly broad, oval or round, or sometimes transversely o\ .i Resin cells rather numerous, usually very long, the resin scatteriiig in small globules. Material silicitied. Cretaceous near Medicine Hat, Alberta; Tertiary of Kettle Kiver, near Midway, British Columbia. CLFRFSSOXYI.ON 839 13. * * C. conMncbtnM, i'enh. TraHSVtrs*. Tracheids in reRular. radial rows, rounded, very uniform, 44* 44 M broad, the w..l U 1 2.5 ^ ,h,ck. Growth rinR. prominent. alHiuMo in a radul extent 0/22 mm. ; the summer wood thin, compoHed of 2-4 rows of iracheid*. the latter al)out 22 ^ wide, the walls i7.5 u thiclT Kesm pa»»aKfH and resin cells wholly wantinK. Worm burrows are fre-' quent and show copious, exudation of resin, which W^ often preserved the adjacent structure from decay. F":«-rvco AW/ii/. Ray cells of one kind only, straight; the upper and lov^^r walls thin and not pitted ; the terminal walls thin, not pitted. chicHv curved '• the lateral walls with oval, bordered pits, about 1-2 per tracheid, the oblong or broadly lenticular orifice nearly as long as the pit ; the ceils equal to alwut 4 tracheids. Bordered pits round, lar-c, 10 abroad • in I or sometimes 2 rows, the orifice round. ' raii,:ential. Rays 1 -seriate, the cells thin-walled, round, 19 ^ broad. Material silicified. SpecimcrLS r-pre.sented by small fragments of a stem. Comanche Cretaceous (?) norttrwe.st of Ashland, Clark County, Kan.sa» (Pro>ser). 18. *• C. pulch«UttBi, Knuwiton " Tmnsverse. The pith is well pre.se-ved and onsi.sts, when vieuccl under the microscopi of numerous large, rather hick-walled cells with an ellnic or nearly circular outline. The i. ger cell.s, which have a diameter of .05-.08 mm , occupy the censer, from which they de cr«-av in size and pa.ss more or less gradually into the mtclullarv ray- The rays are very numerous and pa.ss in nearly a straight line to the circumference. No trace of bark remains. The tracheids are arranged with great regularity in radial rows, and are remarkable for their .small size, particularly where they are in contact with the |)ith As the medullary rays diverge, new layers of tra lieids are ntercalated to hll up the .space. The line of demarcation l,ctw..i he annual layers is generally well defined, the fall « .fl consisting ..; 8 com- pressed cells in ea< h radi;il row. The spn .g wood coiisi.sis ,.f much larger cells, which have a diameter of .025-035 v. m. i hese ci are mor. nearly hexagonal than the others, and, dec a.sing gradi. v in size, pa.ss into the next ring of fall wood. " Raihal. In this section the tracheids an seen to be iont nd ]» ided With a single longi' dinal ro« of border, d pits, Ah it' h can., rage outer diameter of .uiy-.o^i inm. The inner cir. '- ihc pit- is .ailur small, with a diameter of .005-.006 11 n. Tl cut up into comparatively short cells, e.u h o of five or Nix of the tracheids; marViin- si the walls of the rays, but the real state of lii (Jetrifying materia!, which b.as evidently 'W. original structure The resin tiucts (tt-lis, r> sist of a chain of short, regular cells hid ..n the end- The individual cells ai ,8- usually nlled with minute globules of .Market mailer medullar rays are ' ' \ L-riJig the spa e ' to i>e absent from lay !»! masked by the A hat lisorganized the lumerous. These con- slightly constricted at iini in length, and are fl 340 ANATOMY OF THE GYMNOSPERMS " Tangential. The medullary rays are very abundant. They are always simple and consist of a single layer, which ranges from i to 1 5 cells in height, the average being about 7 or 8. The tracheids do not show bordered pits on the tangential walls, a fact of considerable impor- tance" (Knowlton). Remains silicified. From the Potomac Formation at Spring Hill, Virginia (Knowlton). 14. * * C. arkanaanum, Knowlton " Transverse. The annual ring is either entirely absent or so obscured by the mass of crushed cells as to be indistinguishable. In a single, exceptionally well-preserved spot the tracheids are seen to be arranged in nearly uniform radial row.s, there being generally about 3 or 4 rows between 2 medullary rays. The rays are abundant and consist of a single cell. " Radial. The tracheids are rather thick-walled and provided with a single row of pits. The pits are rather distant, the outer circle having a diam- eter of .01 1 -.01 45 mm., and the inner a diameter of .0028-.0048 mm. The medullary rays are abundant, and usually only a single series thick, although a few may be found with 2 .series of cells in the center. " Tangential. The material is not sufficiently well preserved to determine the medullary rays satisfactorily" (Knowlton). Remains silicified. From the Tertiary deposits (Orange sands) of Poinsett County, Arkansas (Knowlton). 15. • • C. Dawaoni, Penh. Transverse. Growth rings variable, chiefly medium to broad. Tracheids of the spring wood large, thin-walled, conspicuously squarish, and passing gradually into the u-sually thin but rather prominent summer wood, which may occasionally become thicker and without definite internal demarcation. Resin passages wholly wanting. Resin cells numerous and conspicuous throughout the growth ring, often in more or less prominent, tangential row. Medullary rays prominent, resin- ous, I cell wide but rather broad, distant 2-9 rows of tracheids. Radial. Medullary rays devoid of tracheids. Ray cells resinous, contracted at the ends, equal to 5-6 spring tracheids ; the upper and lower walls thin and sparingly pitted ; the terminal walls straight, or sometimes strongly curved, not pitted or locally thickened ; the lateral walls with round or oval pits, 1-2 per tracheid in vertical series, or in marginal cells and low rays, or over very broad tracheids, becoming 4 per tracheid. Bordered pits large, in i row, often more or less in pairs, and so, over broad tracheids, becoming more or less 2-rowed. Resin cells numerous, 35-40 fi wide, 200 /i long. Tangential. Medullary rays of one kind only and i -seriate; the cells rarely in pairs, large, thin-walled, oval or oblong, usually brc-id, ant! often becoming transversely oval in all except the terminal cells. Resin cells as in the radial section. CUPRESSOXYLON 241 Material silicified. Eocene of the Great Valley and Porcupine Creek groups, the province of Saskatchewan; Cretaceous of the south Saskatchewan near Medicine Hat, AlberU. 16. C. Watdi, Knowlton " Transverse. Material too fragmentary and too poorly preserved to show the annual rings to the naked eye, but they are apparent under the microscope. The fall wood consists of 3-6 or 3-8 compressed cells m radial rows. The spring wood contains some very large cells, with a diameter in some instances of .062 mm. The number of cells in each row of tracheids varies according to the width of the annual ring, there being frequently as much as 100. Large intercellular spaces occur, especially where additional rows of tracheids have been introduced. "^tfrtVfl/. Tracheids provided in i row, or, in some instances, with 2 lon- gitudinal rows of bordered pits. They occupy the center of the cell, and are in close relations, almost touching in some cases The larger have a diameter of .02 mm., and the smaller a diameter of .015 mm The medullary rays consist of typical parenchymatous tissue. The individual cells are short, covering a width of 4-8 tracheids. Pits on the lateral walls of the rays not observable, possibly due to the poor state of preservation. The resin ducts (cells) are not very numerous. They are of nearly the same size and shape as the tracheids, and in fact look very much like tracheids with transverse partitions Thev are almost always empty. " Tangenlial. The tracheids are not provided with pits on the tangential walls, Of at least none have been detected. The medullary rays in many cases are 2 erse. Annual rings very ..harply marked, 3-4J mm. broad. Under the microscope the cells aie shown to be arranged in strict radial rows, and in the b?ind of summer wood consist of a layer of 18-30 cells more or less completely lignified. In the outer layers of this lignified band of fall wood the lumen of the cells is reduced to a minimum. The lumen is in the form of an ellip.se, of which the long diameter is less than .01 mm. and the short diameter .ilxjut .005 mm. In the immediately following layer of spring wood ilie cells are very large and thin-walled, measuring .08 mm. in long, and CUPRESSf>XYLON 2-J3 .05 mm. in short, diameter. In the .summer wood the cell.s ijecome smaler and more nearly hexagonal in outline, and pass abruptly into the band of fall wood. ' "Radial. In this section, as in the transverse, the demarcation between fall and spring wood is very clearly marked. The walls of the cells in the spnng and summer wood are the only ones provided with bor- dered pits, and in these they seem not to have been very abundant, or at least are not preserved in a manner capable of demonstration These pits are usually arranged in 2 parallel rows, although in some cases there is but i row, when it occupies the center of the cell. The pits are large, and when in 2 rows take up nearly the entire width of the cell. The diameter of the outer circle is in extreme cases fully .025 mm., the average being about .02 mm. ; the diameter of the mner circle is only .0025-.004 mm. The medullary rays are observed to be numerous, with the individual cells very long. The latter are not, however, very high, and they are thin-walled. The pits on the lateral walls are not recognizable. The resin ducts are moderately numerou.s. They are composed of a chain of .short, thin-walled cells .IS-.2S mm. in length, and are partially filled with a dark mass repre- senting the resin. " Tangential. In this section the medullary rays are observed to be com- posed of a single series of cells which ranges from 3 to 30 in number It is rare, however, to find them with as few as 3 or as many as 30 cells, the average number being from 8 to 15. Bordered pits have not been observed in this section " (Knowlton). Material silicified. Cretaceous (?) of Emmet County, Iowa (Knowlton). 20. C. McGeei, Knowlton " Transverse. The tracheids are arranged in strictly radial rows. The annual ring is broad, consisting in some cases of as many as 50 or 60 of the larger, and 10-16 of the smaller, thick-walled cells. The larger cells are mostly quadrangular in outline and have a diameter in some instances of .08 mm., the average being about .068 mm. The cells of the fall wood have very thick walls and are much flattened. Intercellular spaces are frequently observed, particularly where ad- ditional rows of tracheids have been intercalated. The medullary rays are moderately numerous. "Radial. The large size of the tracheids is verj- clearly shown, and they make up the bulk of the section. The tracheids of the fall wood are, of course, much smaller, and are covered with but a single row of pits. The bordered pits are very close together on the summer wood, and are always in 2, and in some exceptionally large celLs, in 3 rows. They are also very large, the out.r circle having a diameter of .02- .025 mm., and the inner of .00S-.008 mm. The walls of the medul- lary rays are marked by large, oval jwres, from 1 to 3 of which occupy the width of a .single wood cell. The resin ducts consist of a chain of short, small, thin-walled cells, which now contain a .small quantity of granular matter, representing probably drops of resin. 244 ANATOMY OF THE GYMNOSPERMS The individual cells have a length of .12-.2S mm., and a diameter of about .05 mm., slightly less, it will be observed, than the tracheids among which they run. " Tanf^ential. The medullary rays are always simple ; that is, they consist of but a single row of cells, which varies from 2 to 49 cells in height. The tracheids are provided on the tangential walls with a few scattered, bordered pits. These have a diameter of .016-.021 mm." (Knowlton). Remains silicified. Specimens represented by a trunk nearly 40 feet long and almost 2 feet in diameter. Potomac Formation at Washington, '^.C. (Knowlton). I?~ 21. C. Calli, Knowlton " Transverse. The annual rings are very distinct, being marked by a layer of fall wood 6-15 or more cells in thickness. These cells are very thick-walled, the lumen being reduced to a mere line. The cells of the spring wood are very large and begin abruptly at the ring, and gradually diminish in .size until they reach and pass into the fall wood. The medullary rays as seen in this section are numerous and are sepa- rated by 2-4 rows of tracheids. "Radial. In the spring and summer wood the tracheids are very broad and provided with 2-3 rows of regularly and closely packed bor- dered 1 it ;. These pits have an average diameter of .012 mm. and an average inner diameter of .003 mm. The medullary rays are thin- walled and in some ca.ses, at least, provided with pits, of which there are usually 3 in thickness of each tracheid. The resin tubes consist of a chain of short, rectangular cells ; they are moderately numerous. " Tangential. The medullary rays are arranged in a single series of super- imposed cells, which varies from 2 to 25, the ordinary number being 6-15. The tracheids are not provided with pits on the tangential walls" (Knowlton). Remains silicified. From the Tertiary clays of Greene County, Arkansas (Knowlton). 11. • JUNIPERUS, LiN\. Plates 40 and 41 Trans'i'erse. Growth rings generally narrow, often unconformable and coalescent on the narrow side ; the summer wood usually thin but dense. Resin passages wholly wanting. Re.sin cells rather numerous, prominent, and chiefly in tangential bands, often giving rise to the appearance of secondary growth rings. Radial. The numerous and often very resinous rays chiefly without tra cheids. Ray cells with thin and entire or sometimes coarsely pitted terminal walls ; the lateral walls with bordered pits. Bordered pits round or oval, chiefly in i row, generally numerous. Tracheids wholly without spirals. Tangential. F'u.siform rays wholly wanting. Ordinary rays i-seriate, some times 2-seriate in part, the cells oval, chiefly broad. JUNIPERUS 245 Synopsis of Species I. Ray cells (tangential) oval to round or transversely oval, resinous, conspicuously broad Ray cells (radial) resinous throughout. 4. • J. californica. Ray cells (radial) locally resinous. Rays usually higher (tangential) than in No. 4 5. J. utahensis. 2. Rays (tangential) rather broad, the cells oval to round, chiefly round, sometimes in pairs, resinous Bordered pits (radial) numerous, usually more or less distant. Rays (tangential) rather high, more or less 2-seriate or the cells in pairs ; the cells chiefly very round, rarely transversely oval. 9. J. pachyphlaea. Rays (tangential) low, the cells rarely in pairs, round to oval, not trans- versely oval 1. • J. virginiana. Bordered pits (radial) numerous, usually crowded into compact series. Rays (tangential) with conspicuously and uniformly rounded cells. 10. J. monosfwrma. 3. Ray cells (tangential) chiefly oval, the rays low, barely resinous Summer wood of 2-4, rarely of 10, tracheids. Pits on the lateral walls of the ray cells chiefly 2 per tracheid. 11. J. occidentalis. Summer wood conspicuou.sly thicker. Pits on the lateral walls of the ray cells 1-4 per tracheid. 6. J. sabinoides. 4. Rays (tangential) narrow, the cells oblong to oval, chiefly oblong Pits on the lateral walls of the ray cells chiefly 2 per tracheid. Ray cells resinous. Terminal walls of the ray cells strongly pitted. Rays with narrow tracheids. ' . J. communis. Terminal walls of the ray cells thin and not pitted. Rays without tracheids. 3. J. rigida. Pits on the lateral walls of the ray cells large, 2-4 per tracheid, obscurely and irregularly bordered. 2. J. nana. I'its on the lateral walls of the ray cell.i not very large, chiefly 4 per tracheid. Ray cells sparingly resinous. 8. ]. sabina. 'St «™"s, flat. Resin cells about 20 /* broad, 100-130 ^ Tangential. Rays sometimes 2-seriate in part, low ; the cells small, nar- rowly oval to round, chiefly round, thick-walled, resinous. A tree 20-30 m. high, with a trunk .60-1.35 m- in diameter. Wood light, soft, not stronfe, brittle, very close and straight grained, compact, easily worked, very durable in contact with the soil, odorous. Relative specific gravity ^ g Approximate relative fuel value .g", , Coefficient of elasticity in kilograms on millimeters' '. '. 670 Ultimate transverse strength in kilograms . . 316" Ultimate resistance to longitudinal crushing in kilograms 6750" Resistance to indentation to 1.27 mm. in kilograms . 2^76 (Sargent) • 01 ■ Nova Scotia; uncommon about Ottawa, but becoming more common westward throughout Ontario, abundant at Bay of Quinte, thence south- ward, crossing the St. Lawrence River midway between Montreal and Lake Ontario (Macoun); southward from New Brunswick to Tampa Bay, Florida ; westward through Texas, Nebraska, Kansas, and Okla- homa to the looth parallel, thence north to northern Michigan, Wiscon- sin, and Minnesota ; in the Pacific region through the mountains of Colorado and British Columbia to Vancouver Island (Sargent). Pleistocene of the Don Valley, Toronto. Material not petrified, but remarkably well preserved in its natural state, and exhibiting the characteristic odor when cut. JUNIPERUS 347 2. J. Sana, Willd. ( "<»w moH Junifer Trann'trse. Growth rings very variable and unconformable, the tracheids very small throughout. Summer wood thin, of 3-6 tracheids, rather open, often double, the transition from the sprinjj wood gradual. Spring wood broad, the tracheids squarish-hexagonal, not very uni- form, small, the walls medium, the general den.sity varying greatly in different ring.s. Medullary rays inconspicuous, 1 cell wide, distant 2-10 rows of tracheids. Kesin cells numeroas, prominent, distinctly zonate Radial. Rays very sparingly, if at all, resinous throughout, wholly devoid of tracheids. Ray cells variable in height, chiefly straight or becom- ing contracted in the summer wood, equal to 7-8 spring tracheids; the upper and lower walls thin, with broad, unequal, and usually rather distant pits; the terminal walls thin, often curved, entire or locally thickened ; the lateral walls with large, very prominent, oval pits with an obscure and unequal border, 2-4, or in the summer wood 2, per tracheid. Bordered pits numerous, large, as broad as the tra- cheid, in 1 row. Pits on the tangential walls of the summer tracheids numerous, large, and open. Resin cells 20 /i wide, about 165 /i long. Tangential. Rays rather numeroas, low to medium ; the cells equal, rather uniform and oblong, sometimes oval, the walls thin. Of uncertain range in the northern parts of the continent ; Lake Mistas- sini ; the Shickshock Mountains, Gaspd ; Bow River, Alberta ; Rocky Mountains from Silver City westward to the summit of the Selkirks in latitude 51°; also the south and north Kootenay passes (Macoun); Labrador southward to Massachusetts and New York, thence westward to Michigan, Colorado, and Utah (Britton). 3. J. rigida, Sieb. et Zucc. /af. = Afuro Transr-erse. Growth rings broad, the structure rather open throughout. Summer wood very thin, of 3-4 tracheids, the transition from the spring wood rather gradual. Spring tracheids conspicuously hex- agonal, rather thin-walled, uniform in regular rows. Medullary rays not very prominent or resinous, 1 cell wide, distant 2-12 rows of tracheids, more rarely 32. Resin cells prominent, usually distant in very narrow zones of occasional growth rings. Radial. Rays somewhat resinous throughout, devoid of tracheids. Ray cells chiefly .straight or somewhat contracted in the summer wood ; the upper and lower walls medium, unequal, distinctly perforate with broad and unequal pits ; the terminal walls thin, often curved, entire or locally thickened ; the lateral walls with rather large, oval, nar- rowly bordered pits, the broadly lenticular orilice becoming oblong m the summer wood, 1-2, or in the marginal cells 4, per tracheid. Bordered pits round, somewhat distant in 1 row, not very numerous. 248 ANATOMY OF THE GYMNOSPERMS Pits on the tangential walls of the summer tracheids rather numerous but not very large or prominent. Resin cells few, 15 u wide, 185- 240 fi long. Tangential. Rays somewhat numerous, medium ; the cells chiefly equal, rather uniform, oblong, more rarely oval and broader. 4. * J. callfonilca, Carr. Juniptr Transverse. Growth rings variable, more or less eccentric and often coalescent. Summer wood thin, chiefly of 3-6 tracheids, not very dense, pas.sing somewhat abruptly into the broad spring wood. Spring wood rather open, the tracheids squarish, the walls medium. Resin cells numerous and conspicuous, chiefly in broad, open bands Medullary rays very prominent and resinous, 1 cell wide, distant 2-1 1, rarely 17, tracheids. Radial. Ray cells very resinous, more or less contracted at the ends, equal to 5-7 spring tracheids; the upper and lower walls medium' and entire or remotely pitted, becoming conspicuously thicker at the ends of the cells; the terminal walls thin, curved and entire or straight, locally thickened or even coarsely pitted ; the lateral walls with oblong pits, chiefly 1, or in the marginal cells and low rays 2-4 per tracheid. Bordered pits broadly elliptical, rather numerous, the orifice rather large. Pits on the tangential walls of the summer tra- cheids numerous and prominent, rather large, the orifice bell-shaped. Resin cellj- about 12.5-20/* wide, and many times longer, upwards of 2 1 s /t. Tangential. Rays low and rather broad, very resinous, the cells from nar- rowly oval in the lowest rays to round or more rarely transversely oval, chiefly round. A small tree rarely 6-9 m. high, with a trunk .30-60 m. in diameter. Wood light, soft, very close grained and compact, very durable in contact with the soil. Relative specific gravity Percentage of ash residue (Sargent) 0.6282 0-73 Dry slopes and plains of the lower Sacramento River, southward through the California coast ranges to Lower California ; spreading inland aloiii; the coast mountains to their union with the Sierra Nevada, throu(,'h which it ranges northward as far as Kernville, descending to 2600 feet ; desert .slopes of Tehachapi .^Iountains, and abundant on the northern foothills and on the seaward slopes of the San Jacinto and Cuyamac.i ranges (Sargent). From the Quaternary deposits (lowani") of the Klamr! . -iver, Orleans, Humboldt County, California, in blue, sandy silt at a d. ith of 150 feet Material very slightly silicified and in a good state of prv - ervation. JUNIPERUS 2^5 5. J. utabenaU, Lemm. Juniftr ^""'^r'M ??/'' 'k"^;' ""'[y ^='""^''=' '^''''"y 'l*'"- •''"">"'" *o«i very thin, of 2-4 trachcids, the transition to the spriiir wood somewhat hexagon-.! ''1?'^ wo««„ra.her open, the trachefds Lu^. ^uar^S fe n n "" "'^'^''^^ compressed, rather large, the wals medium. ThhI^ , numerous, conspicuous, in very open bands in both the spring and summer wood. Medullary rays very prominent and re,in tlnr.^ { cells more conspicuously contracted at the ends and dis- tinctly less resmous than in the preceding, the resin chiefly in ^rmina^ masses, equal to 6-,o spring tracheids^ the upper and^ower waUs un forr^^'r "'•^■'r^ »» '»>e ends of the cells, thickish rSr uniform, ob.scurely pitted, if at all; the terminal walls often curved and coarsely pitted ; the lateral walls with oblong pits, often wXan obscure border, chiefly ,-2. or in the lowest rtys 4 per tracheid Fits on the tangential walls of the summer tracheids veVy numerous and large, but less open and prominent than in J. californica Resin .^ttngtlirs.*''^' '-'' "'"^- '^'"^ - "-^^-'^ ^' ^«^ '^ - - TaugeutiaL Ra>^ somewhat resinous, the cells thick-walled, chiefly trans- versely oval or oblong, usually broader than in No 4 and much shortened vertically. t » " uiuun A small tree 6-9 m. high, with a trunk .60-.90 m. in diameter. Wood light, soft, close grained, compact, very durable in contact with the soil. Relative specific gravity Percentage of ash residue . . . (Sargent) We.stem base of Wa.satch Mountains, Utah, to eastern California and south through the Great Basin to southern California; the San Fran- cisco Mountains of eastern Arizona (Sargent). 6. J. sabinoidet, Ne^s. Cedar. A'aci Cedar ^'""/n^nn" ^T"' n"^' very variable. Summer wood rather dense and ^n^"^ 15 ""^' ♦!:='*=^'^'ds, often double, chiefly much less than the ^pnng wood, into which it passes gradually and which it sometimes ^"tt^ """"^ *''°** "i"'^^^' """"ewhat open, but the demarcation from the summer wood obscure. Resin cells numerous, not verv resinous or prominent, usually in somewhat compact zones, chiefly of the summer wood. Medullary rays not very prominent, 1 cell wide, distant 2-8, rarely 12, rows of tracheids Kadml. Ray cells rather resinous, equal to 5-10 spring tracheids; the S '. '7",^^'=' I^'her thick, variable, frequently pitted he terminal walls thm and not pitted except in the marginal cells- 0.5522 0.75 250 ANAIOMY OF THK C.YMNOSF'EKMS the lateral walls with 1-4 pilH per trachcid. liordircd pits numerauK, In I row, round or vertically compresNed in compact niws, the len- ticular orifice large. Pit* on the tangential walU of the Hummer tracheids numerous and prominent. Kesin cells not very numerous, 15-20 fi wide and 150-375 u long. Tangtntial. Rays usually very low, the cells oval to oblong, not broad, chiefly oval, barely resinous. A tree 11-15 m. in height, with a trunk upwards of .30 m. in diameter. Wood light, hard, not strong, very close grained, compact, very durable in contact with the soil. Relative specific gravity 0.6907 Percentage of ash residue 0.7 Approximate relative fuel value 68.75 Coefficient of elasticity in kilograms on millimeters . . 734. Ultimate transverse strength in kilograms 200. Ultimate resistance to longitudinal crushing in kilograms 8505. Resistance to indentation to 1.27 mm. in kilograms . . 4464 (Sargent) ^^ Valley of the Colorado River, western Texas (Sargent). 7. J. communis, Linn. Juniptr. Ground Ctdar Transverse. Growth rings medium, veiy variable. The chiefly thin and dense summer wood often double, sometimes equal to the spring wood, into which it passes very gradually, the line of demarcation obscure. Tracheids of the usu.illy broad spring wood small. Resin cells rather numerous, usually not very prominent, in 1-3 very narrow zones in each growth ring, the contiguous tracheids rarely becom- ing resinous so as to form a strongly resmous zone. Medullary rays numerous, i cell wide, distant 2-8, or more rarely jo, rows of tracheids. Radial. Rays uniformly resinous throughout, tracheids occasionally pres- ent and marginal. Ray cells somewhat contracted at the ends, equal to 5-6 spring tracheids ; the upper and lower walls thick, unequal, rather frequently pitted , the terminal walls thin, entire, locally thicli- ened or sometimes coarsely pitted ; the lateral walls with unequally bordered, oval pits having a large, lenticular orifice, 1-2 per tracheid. Pits on the tangential walls of the summer tracheids rather numerous, not very large or prominent. Resin cells 12.5-15 /i wide, 125-200 /* long. Bordered pits round, equal to the tracheid, in i row, rather distant, or when more crowded becoming elliptical. Tangential. Rays numerous, low, narrow, resinous ; the oblong cells thick- walled. A prostrate shrub with ascending branches, forming dense mats upwards of 5-7 m. in diameter and 1-1.30 m. high. JUNIPERIS 251 Kroni Labrador lo Jhc Pacific (Maeoun); southward to New Ji-rney am! ;'cnn.sylvaiiia: wijt ,ird to Michigan and wcMcrn Ntl>ra»ka, thentt; Kouthward throuKh the Kmky MounlaiiiH to New Mexico (Britton). 8. J. Mbina, Linn. Shrubby Rtd Ctdar Transverse. Growth rings unequal, often coalencent on the narrower side. The thin .summer wood of 3-8 tracheidit, rarely forming the entire ring, in the broader ringH l><.coming double or treble. Spring wood open, the trachtid* large arid thin-walled. Keitin cell.-i not very numer- ous or prominent, chiefly narrowly zonate in the spring wood, often .showing extensive but local aggregations when they liecome large, rounded and lootwly grouped in irregular masses with the partial formation of resin canals. Medullary rays inconspicuous, distant 2-25, rarely 37, tracheids. Radial. Ray ceils very sjAaringly resinous, chiefly straight, equal to about S spring tracheids ; the upper and lower walls thin and entire or with rather distant pits ; the terminal walls thin and locally thickened or coarsely pitted ; the lateral walls with rather prominent pits with a broadly lenticular or oval orifice, the border rather obscure, 1-2, chiefly 4, per tracheid. Bordered pits numerous, as broad as the tra- cheids, generally elliptical in i compact row, the orifice large. Pits on the tangential walls of the summer tracheids .somewhat numerous and prominent. Kesin cells about 15 fi wide, 125-150 /t long. Tangential. Rays all narrow, the cells chiefly narrowly oval to oblong, the walls thin, \ ariable ; when of a single cell, the latter is high, lenticular. A depressed, usually procumbent shrub, seldom more than 1.20 m. high (Britton). On exposed slopes and river banks from Anticosti, Nova Scotia, New Brunswick, Quebec, and Ontario, across the prairie region to the sum- mit of the Rocky Mountains at Kicking Horse Pass (Maeoun); from Maine, westward through New York, Minnesota, and Montana (Britton). 9. J. pachyphlat, Ton-. Juniper. Checkered-Barked Juniper Transverse. Growth rings very narrow and unequal, eccentric. Summer wood dense and thin, of 2-6 tracheids, the transition to the spring wood somewhat gradual. Spring wood somewhat open, the tracheids in regular rows. Resin cells numerous, chiefly in the spring wood, irregularly zonate. Medullary rays very prominent and resinous, i cell wide, broad, distant 2-8 tracheids. /Radial. The resinous ray cells equal to 4-13 spring tracheids; the upper and lower walls medium to thick, entire or remotely pitted ; the ter- minal walls strongly pitted ; the lateral walls with rather conspicuous, lenticular pits about 1-2, more rarely 4, per tracheid. Bordered pits 25a ANA'lt>MV OF 1HE GYMNOSPERMS It III ill ill round, numeroun, li«cominK very iimall and obKure in the Rummer wood, the round orifice becuminK lenticular towards the Kummer wood l'it!»on the iiinKcntial walls of the »ummer tracheid* numerou», medium^ t1.it. Renin relU al>out 20 /i wide, i 65-400 ^ Irang. ranf;eHliitt. Kays medium, often 3.» riate in part, the celU broadly oval or round, rather thick-walled. A tree 6-15 m. high and .60 m. in diameter. Wood light, soft, not strong, brittle, very cIom grained, compact, suscep- tible of a line poliiih. Relative specie gravity q -gjg Percentage of ash residue (Sargent) 0.1 1 Mountains of western Texas, southern New Mexico, and Arizona south of latitude 34° ; southward into Mexico (Sargent). 10. J. numotpenu, Sarg. Juniptr TraHn>erse. Growth rings chiefly broad, very variable. The prominent but u.Hu.illy very thin summer wood dense, of 3-7 trachelds. often double ; the transition from the spring wood somewhat gradual Spring wood somewhat dense, the tracheids variable. Resin cells very pronv ment and resinous, numerous, in compact zones chiefly in the sprintr wood. Medullary rays very numerous and prominent, broad, i cell wide, distant i-io rows of tracheids. Radial. Ray cells resinous throughout, more or less conspicuously con- tracted at the ends, equal to 6-8 spring tracheids ; the upper and lower walls thick, rather uniform, frequently pitted; the terminal walls coarsely pitted ; the lateral walls with small, round, bordered pits with a lenticular-oblong but small orifice, chiefly 2, but in low rays and marginal cells often upwards of 6, per tracheid. Bordered pits numer- OU.S and in 1 compact row, round or vertically compressed, neariy as broad as the tracheid. Pits on the tangential walls of the summer tracheids very numerous but small. Resin cells about i s u wide. 200 u and upwards long. Tangential. Rays numerous, rcsino -, low ; the broad cells oval or round somewhat uniform. A stunte i tree 6-9 m. high, and a trunk upwards of .60 m. in diameter. Relative specific gravity 0711Q Percentage of ash residue „ 78 (Sargent) '° Gravelly slopes between 3500 and 7000 feet elevation, eastern base of Pikes Peak, to the mountains of western Texas ; through New Mexico and southern Arizona to southern California (Sargent). ABIKS '53 11> J. cccl, Hook Tnnn.'trst. (growth ringi. usually verv narrow ; th, den^L summer wood of a-4, rarely lo, trachcids, passinK ither abruptly into th. rather open •pring wc,«| i the iracheid. small »nd thitk-walled. .Sprl„« wood rather optn, but the tracheids rather ,m,. ' ..nd usually much rounded Kciin fell, abundant and ptomincnt, thief!) in the sumu,er and outer spring wood in open or = ompa. ( /ones. Medullary ravs numerous rather promln^ nt, not very reninou*. i ( dl wide, di»taii'( i^ rarelv 13, rows of trachiids. ' Ra^l. Kay cell, verv sparingly re.inou., usually straight or wmcwhat contracted at th- en Is. equ.,1 to ^ o spring tratheid.,; th. upper jnd lower wall, thick.sh entire or .bsuntly pitted; the terminal wall, •trongly pitted : the lateral » ais ,Mth small, oval, bordered pi(«, the orifice o».long. 1-3, m -re rare) 4, |Hr tracheiil throughout. Hordtred pit. round, numerous, in 1 r. « becoming obsci, or wantini; in the .ummcrwood. Pits on the tan ntial xv,,.,, „( „e sun.mrr tracheids numerous, but usually small and often oi^ure. Kesm cell, numerous 20^ wide, 140-275 /I loHK. ' TangtHtial. Ray.s generallv lo\v, of a few ..Us only he cells round K. oblong, not very broa.! chicily oval. A tree 6-15 m high, with . trunt . .:o -mo " , i di.^met - : often becoming a low, much-branched shrui>. Wood light, soft, very close grained, r<-,i„.at, vtu „ rabic in .ontact with the soil. Kelatrve specific gravity o C7fit Percentage of ash residue 01 (Sargent) °'- Dry, rocky ridges and prairies (, the Blue Mountain.s and high prairies of eastern Washington and Oregon ; the Cascade Mountains of Oregon • the valley of the Klamath River, California, and south along the hii;h ridge, of the Sierra Nevada Mountainy at elevations of 7000-10,000 feet, to the San Bernardino Mounuins (Sargent). Ji± 12. • ABIES, Link. Plates 42 and 43 Tranrverse. r.rowth rings ■ .ually broad with no very clear demarcation between the spring and summer woods. Resin pa.s.sages sometimes present and then imperfectly organized, u.sually In somewhat distant growth rings Resin cells, when present, remote and inconspicuous on the outer face of the summer wood. /'.-v//«/. Ray tracheids not present (except A. balsamea). The terminal wD,(s of the ray cells usually strongly pitted, especially in the summer «oM. Tracheids wholly without spira!>. /■ ngeh,.al. Fusiform rays wholly wantini,' I? nys narrow, strictly i-seriate. 254 ANATOMY OF THE GYMNOSPERMS 11^ Synopsis of Species I. Resin passages present but imperfectly developed* Ray cells (tangential) all broad, oval, or round. Pits on the lateral walls of the ray cells 1-3, rarely 4, per tracheid. Tracheids in regular rows. Resin cells on the outer face of the summer wood. 10. A. concolor. Resin cells wanting. 8. A. bracteata. Pits on the lateral walls of the ray cells chiefly 2, rarely 3-4, per tracheid. Tracheids in regular rows. Resin cells wanting. 9. A. nobilis. Ray cells uniformly narrow, oblong. Pits on the lateral walls of the ray cells obscurely bordered, greatly reduced or wanting in the summer wood, 1-4, or in the marginal cells 6, per tracheid. Resin cells wanting. 11. A. firma. 2. Resin passages wholly wanting Ray tracheids present, few. Resin cells (transver.se) wanting, Ray cells (tangential) uniformly narrow, oblong. Pits on the lateral wallsof the ray cells i -4, rarely 8, per tracheid. 4. * A. balsamea. Ray tracheids wholly wanting. Resin cells wanting. Ray cells (tangential) uniformly narrow. Fitson the lateral wallsof the ray cells 1-4, rarely 8, per tracheid. 4. * A. balsamea. Pits on the lateral walls of the ray cells obscurely bor- dered, greatly reduced or wanting in the summer wood, 1-4, or in the marginal cells 6, per tracheid. 1 1 . A. firma. Pits on the lateral walls of the ray cells more or less obvi- ously bordered, especially in the summer wood, chiefly 2 per tracheid. 1. A. Fra-seri. Ray tells (tangential) variable, from round or oval to narrowly oblong. ' Species included in this section should also be looked for under the second section with the same differentiation. ABIKS 255 Pits on the lateral walls of the ray cells 1-4, in the mar- ginal cells rarely 5, per tracheid. Upper and lower walls of the ray cells strongly pitted throughout. 2. A. lasiocarpa. Pits on the lateral walls of the ray cells 1-2, or in the mar- ginal cells upwards of 4, per tracheid. Upper and lower walls of the ray cells sparingly pitted in the spring wood. 3. A. Veitchii. Resin cells scattering on the outer face of the summer wood. Ray cells broad (tangential), oval to round. Pits on the lateral walls of the ray cells small, round, or oval, at first obscurely bordered, but toward the summer wood with a distinct border and narrow orifice. Pits on the lateral walls of the ray tells i -4, soon becoming 2, and in the summer wood i, per tracheid throughout. Upper and lower walls of the ray cells thin, not obviously pitted. Ray cells (tangential) verj- broad and large. 7. A. grandis. Pits on the lateral walls of the ray cells 1-2, rarely 3, or in the marginal cells sometimes 5, per tracheid. Upper and lower walls of the ray cells thick, un- equal, coarsely but very unequally pitted. Ray cells (tangential) chiefly ova!, rarely in pairs. 6. A. amabilis. Pits on the lateral walls of the ray cells chiefly 2, more rarely i or 4, or in the summer wood i, per tracheid throughout. Upper and lower walls of the ray cells unequal, strongly but imperfectly oitted throughout. Ray cells (tangential) round or oval, not very large. S- A. magniiica. 1. A. Fraseri, Poir. Balsimi. She lialsam Transverse. Growth rings rather thin, variable, the structure open through- out. Summer wood very thin, of 2-6 tracheids, passing gradually into the spring wood. Spring tracheids rather large and thin-walled, f ■ ^1 f' 256 ANATOMY OF THE GYMNOSPERMS squarish, uniform, in very regular rows. Resin cells none. Resin- bearing tracheids few, rather prominent, scattering through the sum- mer wood, more rarely in the spring wood. Medullary rays somewhat resinous and prominent, i cell wide, distant 2-15 rows of tracheids. Radial. Medullary rays sparingly resinous throughout, wholly devoid of tracheids. Ray cells straight, or in the summer wood contracted at the ends, equal to 7-8 spring tracheids ; the upper and lower walls medium, unequal, somewhat dista tly and imperfectly pitted in the spring wood, but strongly pitted in the summer wood ; the terminal walls strongly pitted ; the lateral walls with small pits which become conspicuously bordered in the summer wood where the orifice is reduced to a slit and the pit is round, 1-2, chiefly 2, or in the marginal cells 2-4, per tracheid. Resin-bearing tracheids not numerous, the resin sometimes massive in the summer wood, but forming a periph- eral layer in the spring wood. Bordered pits elliptical, in i row or sometimes in pairs. Pits on the tangential walls of the summer tracheids somewhat numerous but small and flat. Tangential. Rays small to medium, the cells narrow, rather uniform, oval to oblong. A tree 18-24 m. high and upwards of .60 m. in diameter. Wood very light, soft, not strong, coarse grained, compact. Relative s[>eciflc gravity o-3S'i5 Percentage of ash residue 0.54 Approximate relative fuel value 3546 Coefficient of elasticity in kilograms on millimeters . 972. Ultimate transverse strength in kilograms 273. Ultimate resistance to longitudinal crushing in kilograms . 5557. Resistance to indentation to 1.27 mm. in kilograms . . 1048. (Sargent) High mountains of North Carolina and Tennessee, forming somewhat extensive forests on moist slopes between 5000 and 6500 feet (Sargent). 2. A. lesiocarpa, Nutt. Mountain Balsam. Balsam Fir Transverse. Growth rings narrow, uniform, the structure open throughout. Summer wood very thin, rarely upwards of 14 tracheids, the transition to the spring wood gradual. Spring wood of large, squarish tracheids with rather thin walls, uniform in regular rows. Resin cells and resin- ous tracheids wholly wanting. Medullary rays not prominent, barely if at all resinous, I cell wide, distant 2-8, more rarely ij, tracheids. Radial. Rays very sparingly resinous, wholly devoid of tracheids. Ray cells more or less con.spicuously contracted at the ends, equal to about 7 spring tracheids; the upper and lower walls thick, unequal, and strongly pitted throughout ; the terminal walls thin, often devoid of pits ; the lateral walls with obscurely bordered pit.s, the large orifice lenticular, variable, 1-4, or in the marginal cells rarely 5, per tracheid, and distinctly bordered, in the summer wood reduced to 1 per tracheid ABIES 257 and distinctly bordered. Bordered pits elliptical, in 1 row, nearly the diameter of the tracheid. Pits on the tangential walls of the summer tracheids rather numerous, not very large. Resin cells and resinous tracheids wholly wanting. Taugential. Rays medium, the cells variable, from round or broadly oval to narrowly oblong. A tree 20-40 m. high, with a trunk upwards of .60 m. in diameter. Wood very light, soft, not strong, rather close grained, compact. Relative specific gravity 0.3476 Percentage of ash residue 0.44 Approximate relative fuel value 34-6 1 Coefficient of elasticity in kilograms on millimeters . . 762. Ultimate transverse strength in kilograms 202. Ultimate resistance to longitudinal crushing in kilograms 4829. Resistance to indentation to 1.27 mm. in kilograms . . 1015. (Sargent) Summit of House Mountain, south of Lesser Slave Lake ; abundant in Bow River Pa.ss on mountain slopes 5000-7000 feet elevation, extend- ing on the line of the Central Pacific Railroad from Castle Mountain to Selkirk Summit ; abundantly in the Gold and Selkirk ranges, and in the Rocky Mountain region east of McLeod's Lake ; elsewhere in the northern portion of the interior plateau it occurs in scattering groves, generally in localities nearly reaching or surpassing 4000 feet, but even in low valleys in the eastern portion of the coast ranges ; damp situations in the country between Lesser Slave Lake and the Athabasca River ; high, cool valleys in the Rocky Mountains, southward to the 49th par- allel, reaching upward to the timber line (Macoun) ; valley of the Stakhin River in Alaska, in latitude 60° N. ; through the Blue Mountains of Oregon and the ranges of Idaho, Montana, Wyoming, Utah, and Col- orado; on mountain slopes and canons from 4000 (British Columbia) to 12,000 feet (Colorado); rarely forming the prevailing forest growth (Sargent). 3. A. Veitchii, Lindl. /up. = Shirabi Transverse. Growth rings very variable, often very narrow. Summer wood prominent but very narrow, of 3-5 squarish tracheids, the structure open, or again broad and .somewhat exceeding the spring wood, with the structure rather open but the tracheids strongly rounded ; transition to the spring wood gradual. Spring wood open, the tracheids rather large, .squarish, and thin-wallcd, uniform in regular rows. Resin cells and resinous tracheids wanting. Medullary rays not prominent, 1 cell wide, distant 1-20 rows of tracheids. Kiuiial. Rays somewhat resinous in part, and wholly devoid of tracheids. Ray cells chietiy straight, equal to 7-8 spring tracheids, or in the I m 253 ANATOMY OF THE GYMNOSPERMS summer wood becoming very much shorter ; the upper and lower walls medium, unequal, the narrow pits not very numerous, except in the summer wood, often imperfectly formed ; the terminal walls closely pitted, becoming more prominent in the summer wood ; the lateral walls with narrowly bordered oval pits, 1-2, or in the marginal cells upwards of 4, per tracheid, the orifice broadly lenticular or oval. Bor- dered pits round or elliptical, numerous in I row, variable, but chiefly two thirds the diameter of the tracheid, the large orifice round. Pits on the tangential walls of the .summer tracheids few, small, rather open. Resin cells and resinous tracheids wholly wanting. Tangential. Rays not very numerous, medium to high, somewhat resinous, strictly 1 -seriate ; the cells somewhat unequal and variable, chietly round or oval, sometimes oblong. ii 4. • A. balaamea, Mill. Balsam Fir. Balm-of-GiUad Fir. Canada Balsam Fir Transverse. Growth rings thick. Summer wood thin, often, passing very gradually into the spring wood. Spring wood very open, the large tracheids squarish-hexagonal, thin-walled, uniform in regular rows. Resin cells wanting. Medullary rays not numerous or prominent, 1 cell wide, distant 2-8, rarely 1 2, rows of tracheids. Radial. Ray tracheids few, narrow, and very unequal ; the rays barely resinous. Ray cells conspicuously contracted at the ends and equal to 2-6 spring tracheids ; the upper and lower walls medium, unequal, somewhat distantly and finely, but often imperfectly, pitted ; the ter- minal walls coarsely pitted, especially in the summer wood ; the lateral walls with .small, round or oval pits, 2-4, more rarely upwards of 8, per tracheid. Bordered pits elliptical, large, one half the diameter of the tracheid, chiefly rather scattering, in i row or often in pairs, and more or less imperfectly 2-rowed. Pits on the tangential walls of the summer wood not numerous, chiefly quite small. Tangential. Rays medium, the cells narrow, uniform, oval to oblong. A tree 21-27 m. high, with a trunk upwards of .60 m. in diameter. Wood very light, soft, not strong, coarse grained, compact, not durable. Relative specific gravity 0.3819 Percentage of ash residue 0.45 Approximate relative fuel value 38.03 Coefficient of elasticity in kilograms on millimeters . . 819. Ultimate transverse strength in kilograms 220. Ultimate resistance to longitudinal crushing in kilograms 5851. Resistance to indentation to 1.27 mm. in kilograms . . 1202. (Sargent) Abundant in swamps throughout the eastern provinces of Canada, north- ward to James Bay and westward to the Athabasca River in latitude 58" (Macoun); southward through the northern United States to Pennsyl- vania, and along the Allegheny Mountains to the high peaks of Virgini.i ; ■ M ABIES 259 westward through central Michigan and Minnesota and northward along the eastern slope of the Rocky Mountains (Sargent). Pleistocene of the Scarborough Period at Scarborough, Ontario. Material altered by decay, but otherwise in original condition and not petrified. 6. A. nugnillca, A. Murr. Ktd Fir Transverse. Growth rings rather broad. The summer wood upwards of one third the growth ring, the structure open throughout, but the most recent tracheids much compressed radially, transition to the spring wood very gradual. Spring wood open, the large, con.spicuousiy squarish tracheids uniform in very regular rows, thin-walled. Resin cells present on the outer face of the summer woo' It! 8. A. bracteaU, Nutt. Silver hir TraHsi'trse. Growth rings broad. Summer wood prominent, dense, one third the spring wood, into which it passes somewhat gradually. Sprinj; wood rather open, the tracheids large and thin-walled, squarish-hex- agonal, rather uniform in regular rows. Kesinous tracheids wholly wanting. Kesin cells sometimes present and then forming imperfectly organized resin canals in a somewhat continuous zone, within or near the summer wood of distant growth rings. Medullary rays prominent and somewhat resinous, especially in the summer wood, I cell wide. Radial. Kays somewhat resinous throughout, especially in the summer wood, wholly devoid of tracheids. Kay cells .straight or barely fusi- form except in the summer wood, where they are strongly contracted at the ends ; equal to about 5 spring tracheids ; the upper and lower walls rather thin, unequal, rather distantly pitted except in the sum- mer wood, where the pits are numerous, or again in the spring wood locally numerous ; the terminal walls thin, often devoid of pits except in the summer wood ; the lateral walls with prominent, round or broadly oval pits, chiefly 1-3, or in the marginal cells 4, per tracheid. Bordered pits numerous, chiefly elliptical in i row, or often in pairs so that they become more or less 2-rowed. Pits on the tangential walls of the summer wood numerous and extending well into the interior. Kesin cells short-cylindrical, united to form short resin sacs on the outer face of the summer wood. Tangential. Rays medium to high ; the cells chiefly broad, oval, often resinous and sometimes in pairs of much smaller cells. A tree 41-61 m. in height and with a trunk .90-1.20 m. in diameter. Wood heavy, not hard, coarse grained, compact. Relative specific gravity Percentage of ash residue (Sargent) 0.6783 2.04 Santa Lucia Mountains of California, from the northern boundary of San Luis Obispo County, about 40 miles northward ; on moist, cold .soil, occupying four or five cafions at 3000-6000 feet elevation, generally west of the summit of the range (Sargent). 9. A. nobilis, Lindl. Red Fir. Larch Transverse, (growth rings rather broad. The summer wood prominent, hro.i'l, upwards of one half the .spring wood, the structure ihicriy open, but beioming rather dense on the outer face of the growth rini;; transition to the spring wood gradual. Spring tracheids rather l,ir).;t' and thin-walled, squarish-hexagonal, toward the summer wood JKccim- ing unequal and in more or less irregiilar rows. Ke.sin cells locali/til ABIKS 263 to form imperfect resin canals* in a more or less continuous zone in the summer wood of distant growth rings. Medullary rays prominent, somewhat resinous, i cell wide, distant i-S rows of trachcids. Radial. Rays more or less resinous throughout, wholly devoid of ir.i cheids. Ray cells chietly straight, becoming conspicuously fusiform in the summer wood, equal to about 8-1 1 spring tracheids ; the uppir and lower walls medium, unequal, more or lcs,s strongly pitted through- out ; the terminal walls strongly pitted ; the lateral walls with round or oval, conspicuously bordered pits, the orifice lenticular or oblong, 1-2, or in the marginal cells rarely 3-4, per tracheid. Uordered pits in I row, sometimes in pairs, round, the orifice large. Fits on the tangential walls of the summer tracheids minute. Resin cells, when present, short-cylindrical and united to form short resin sacs within the summer wood of distant growth rings. Tangential. Rays medium to high, the cells often resinous, chiefly broad but variable from round to oval and oblong, unequal, often in pairs. A large tree 61-92 m. high, with a trunk 2.40-3 m. in diameter. Wood light, hard, strong, rather close grained, compact. Relative specific gravity 0.4561 Percentage of ash residue \ \ 0.3, Approximate relative fuel value . . 45^46 Coefficient of elasticity in kilograms on millimeters . . 1277. Ultimate transverse strength in kilograms 368! Ultimate resistance to longitudinal crushing in kilograms 7256. Resistance to indentation to 1.27 mm. in kilograms . . 1017 (Sargent) * ^ '' Oregon, Cascade Mountains from the Columbia River south to the valley of the upper Rogue River, and along the .summits of the Coast Range from the Columbia to the Nestucca River (Sargent). 10. A. concolor, Lindl. and Gordon White Fir. lialsam Fir Transverse. Growth rings broad, the structure rather open throughout. Summer wood prominent, thin, upward.s of one third the spring wood, into which it passes very gradually. Spring tracheidh medium, squar- ish, thin-walled, and uniform in somewhat regular rows. Resin pas- .sages prominent and rather nunerous but imperfectly formed, very variable, and often large, forming more or less continuous series within the summer wood, often of distant growth rings. Resin cells few, nonresinous, distant on the outer face of the summer wood and distinguished by (1) the siive-plate structure of the terminal wall, and (2) their somewhat advanced position. Medullary r.iys rather promi- nent and somewhat resinous, especially in the summer wood : 1 cell wide, distant 2-7, rarely 10, rows of tracheids. Radial. Rays somewhat resinous, especially in ihc summer wootl. Ray cells conspicuously contracted at the ends throuKhout and equal to 11 ,i Iff M Si 264 ANATOMY OF THE GYMNOSPERMS (>-ii spring tracheids, f)eron»inK shorter in the suntmcr wood; the upper and lower walls r.iilu r thick, untitual, and conspicuously pitted throughout ; jhe terminal wall> rather sparingly pitted, especially in the spring wood '. !he lateral walls with round or elliptical, small, obscurely Iwrdered pits, which becfwne distinctly bordered toward the summer wood, where the broadly lenticular orifice becomes oblong or hnally slitlike, 1-3 per tracheid throughout the spring wood, becom- ing I in the summer wootl. Bordered pits rather numerous in i row, elliptical (i round. Pits en the tangential walls oi the summer tra- cheids rather numerous but not very large, flat. I'its rarely on the tangential w.ills of the ear ier spring tracheids. Resin cells rarely to be stcn. Re.s- passages i..i)crfectly formed of short, rylina.ical resin cells, in interrupted series. TaMf;tittial. Rays num> rous, medium to high, not very broad ; the cells chiefly uniforM', oval, scj letimts round or oblong, r.rely large. A tree 30-40 m. in height, witu a trunk 1. 20-1. 50 m. in diameter. Wood very light, soft, not strong, coar.se grained, compact. Relative specihi; gravity 0.3638 Percentage of ash residue 0.85 Approximate relative fiul value . 3607 Coeftiriint of elasticity in kilograms on millimeters . . 909. Ultimate transverse strength in kilograms 300. Ultimate resistance to longitudinal crushing in kilograms 6237. Resistance to indentatiin to 1.27 mm. in kilograms . . 1248. (Sargent) Moist slopes and canons between 3000 ana 9c 00 feet ekvation, reach- ing its greatest development in the California Sierras; orthern slopis of the Siskiyou Mountains of Oregon ; south along the western slope of the Sierra Nevadas to San Bernardino and San Jacinto Mountains of California; the high mountains of Arizona to the Mogollon Mountains of New Mexico ; northward to Pikes Peak and the Wasatch Mouii tains of Utah (Sargent). 11. A. firmc, Sieb. et Zucc. Jap. = Afomi Transverse. Growth rings broad, the dense summer wood about nnu fourth the spring wood, into which it passes gradually. Spring wood open, the tracheids thin-wallcd, in very regular rows, uniform, larj;t. Resin cells and resinous tracheids wanting. Medullary rays ratlur prominent and sparingly resinou.s, 1 cell wide, distant 2-10 rows ol tracheids. Resin canals present but imperfectly organized, forming' local or sometimes extensive tangential rows on the outer face ol iIk summer wood of distant growth rings. Radial. Medullary rays sparingly resinous, devoid of tracheids. K.iy cells straight, equal to 5-10 spring tracheids, in the summer wood becoming much shorter and distinctly fusiform ; the upper and low r TSUOA ,65 walU medium, unequal, very dparingly pitied, in the summer wood lictominK toniipicuouHly thiclS Rochester. New rorh 14609 USA ^B (716) ♦BI - 0300 - Phone ^S (716) 288 - 5989 - ran I m\ 266 ANATOMY OF THE OYMNOSPERMS Resin passages not present. Resin cells scattering on the outer face of the summer wood. Fits on the lateral walls of the ray cells 2-4, or in the sum- mer wood 1-2, per tracheid ; the resin cells prominent, resinous. 1. T. canadensis. Pits on the lateral walls of the ray cells 1-2, rarely 3, per tracheid. Spring tracheids very large and uniform, conspicuously 4-sided, the walls thin. 5. T. Mertensiana. Pits on the lateral walls of the ray cells very variable, at first 5, soon uniformly 2, and finally I, per tracheid. Spring tracheids squarish-hexagonal. 2. T. Sieboldii. Resin cells on the outer face of the summer wood and also often zonate in the spring or summer wood. Resinous tracheids wanting. Pits on the lateral walls of the ray cells 2-6, finally 1, per tracheid. 3. T. caroliniana. Resinous tracheids in groups or radial series in contact with the rays. Pits on the lateral walls of the ray cells 1-4, chiefly 2, and finally i, per tracheid, the orifice f.nally becom- ing a prolonged slit. 4. T. Pattoniana. 1. T. canadensis, Carr. //em/oci Transverse. Growth rings thin, variable. The thin and dense .summer wood prominent, equal to about one fourth to one half the spriiijj wood, from which the transition is abrupt. Spring wood very o|xn, the large and very thin-walled tracheids conspicuously squari.sb, often elongated radially, very uniform and in regular rows. Resin cells prominent, resinous, not very numerous. Medullary rays very promi- nent, somewhat resinous, I cell wide, distant 2-10 rows of tracheids. Radial. Rays uniformly somewhat resinous throughout, the trach^..as often interspersed. Ray cells somewhat contracted at the ends, equal to 3-5 spring tracheids ; the upper and lower walls medium, unequal, very irregularly and often imperfectly, sometimes very sparingly, pitted ; the terminal walls not very strongly pitted except in the summer wood ; the lateral walls with small, oval pits, at first with a very narrow border, which becomes more pronounced toward the TSUGA 267 summer wood, the lenticular orifice hecominj: oblonjr, 2-4, or in tiie summer wood 1-2, per trarheid. Bordered pits round or elliptical in 1-2 rows, more rarely in 1 row only, th. orifice large. Fits on the tangential walls of the summer wood rather numerous, prominent, flat. Resin cells IS ^ wide, 165-240 /i long Tangential Rays numerous, low to high, not very broad, usually con- stricted at the position of the frequent narrow and oblong tracheids • the parenchyma cells rather equal and chiefly narrowly oval to oblong, sometimes broadly oval. A tree 21-33 m. high and with a trunk .90-1.15 m. in diameter. Wood light, soft, not strong, brittle, coarse, crooked grained, difficult to work, liable to wind shake and splinter, not durable (Sargent). This wood is of great value for construction purposes, where it is to be constantly su'>.merged in water, when it possesses elements of great durability (Bovey). Relative specific gravity o A-yxa Percentage of ash residue • • • 0^5 Approximate relative fuel value ........' 42 20 Coefficient of elasticity in kilograms on millimeters '. ' qoo Ultimate transverse strength in kilograms .... 307 Ultimate resistance to longitudinal crushing in kilograms 614^ Resistance to indentation to 1.27 mm. in kilograms i-iia (Sargent) * • • ■ji4. According to the results obtained by Dr. Bovey in the testing laboratories of McGill University, the following data may be given : Coefficient of strength in pounds per square inch for : 5^'"I'"S 5000 I'"'^'°" 8000 Compression Shear -^ g^ Weight of i cubic foot 33 Abundant on cold soils, Nova Scotia and New Brunswick, and throughout Quebec and Ontario ; northward from Quebec to the northern end of Lake Temiscaming, thence to the eastern extremity of Lake Superior at Agawa (Macoun); through the northern United States to Newcastle County, Delaware, and along the Allegheny Mountains to Clear Creek Falls, Winston County, Alabama ; southeastern Michigan and central Wisconsin (Sargent). 2. T. Sieboldli, Carr. y(//. = Tsuga Transverse. Growth rings narrow, uniform, the prominent summer wood dense, about one fourth to one half the spring wood, from which the transition is gradual. Spring tracheids squarish-hexagonal, rather w 268 ANATOMY OF THE GYMNOSPERMS If r [i thin-walled, uniform in regular rows. Medullary rays not very numer- ous, resinous, prominent, and distant 2-10 rows of tracheids. Kesin cells somewhat distant on the outer face of the summer wood, but readily recognizable. Radial. Kays somewhat resinous throughout, the tracheids wholly marginal. Kay cells chiefly straight except in the summer wood ; the upper and lower walls medium, unequal, strongly pitted, especially in the summer wood ; the terminal walls strongly pitted ; the lateral walls with very small, oval, bordered pits with a lenticular orifice, which soon becomes oblong and narrow, at first very variable and upwards of 5, soon uni- formly 2, and in the summer wood 1, per tracheid. Bordered pits numerous, round or elliptical, in I row, sometimes in pairs. Pits on the tangential walls of the summer wood rather numerous and flat, not very large. Resin cells 20 ^ wide, 150-275 /i long. Tangential. Rays medium, resinous, the cells unequal, chiefly broad but variable, round or oval, more rarely oblong. 3. T. caioliniaiia, Engel. Hemlock Trarsverse. Growth rings medium, variable, the dense and prominent summer wood composed of rather small and more or less rounded tracheids, the transition from the spring wood rather abrupt, often quite gradual, usually much less than, or again upwards of one half, the spring wood. Spring tracheids rather large, uniform and thin- walled in regular rows, usually elongated radially. Medullary rays prominent, not very broad, I cell wide, distant 2-10 rows of tracheids. Resin cells on the outer fac of the summer wood prominent, resin- ous, not very numerous, sometinos ag/regated to form limited but conspicuous and irregular layers on the mner face of the summer wood. Radial. Rays uniformly somewhat resinous throughout, the tracheids prominent, sometimes interspersed. Ray cells not conspicuously con- tracted at the ends except in the summer wood, equal to 6-8 spring tracheids, becoming much shorter in the summer wood ; the upper and lower walls medium, very sparingly pitted except in the outer summer wood ; the terminal walls coarsely pitted throughout ; the lateral walls with small, narrowly bordered pits, the orifice at first lenticular, at length narrowly oblong, at first 2-J5, finally reduced to I, per tracheid in the summer wood. Bordered pits round or elliptical, verv numerous, usually as broad as the tracheid, in I compact row. Pits on the tangential walls of the summer tracheids numerous but small and not very prominent. Resin cells on the outer face of the summer wood 15 ft. wide, 185-310 /n long; those on the inner face very short and cylindrical, irregular and unequal, and forming a con- tinuous series without canals. Tangential. Rays rather numerous, medium, narrow, resinous, sometimes constricted by the occasional and narrow, oblong tractieids ; the cells somewhat ur lal, chiefly oblong but rather variable, and sometimes becoming c TSUCIA 269 A small tree 12-15 m. high, with a trunk .60-75 tn. ir v . ,etcr Wood light, soft, not strong, brittle, coarse graine-i. Relative specific gravity Percentage of ash residue . . 0-4275 Approximate relative fuel value °'*° Coefficient of elasticity in kilograms on millimeters " ' jf,'' U timate transverse strength in kilograms " ,'1 Ultimate resistance to longitudinal crushing in kilograms' 64?o (s\^?eS) '"'"^^^^ • S Dry, rocky ridges; rare and local at elevations of 4000-5000 feet Southern Allegheny region; Bluff Mountain, Pinnacle Mountain New River, Whitesides Mountain, and Devil's Court-House Peak, North Caro- lina; Saluda Mountain, Casar's Head, South Carolina (Sargent) m 4. T. Pattoniana, S6n6c. Mountain Hemlock. Patton Spruce Transverse. Growth rings variable, chiefly rather narrow, the structure usually open throughout. Summer wood very narro^, rather ojen the transition from the spring wood very gradual. Spring trLheid.! rather large and thin-walled, conspicuously squarfsh uniforn, f' regular rows. Medullary rays numerous, broad, , eel wide ralher prominent, distant 2-7 rows of tracheids. Resin passageTsonatimes present though imperfectly formed, generally in T .shoft zone on The ^^Jli^l °^*"'''y ^'''^"' «''°^**' ""«''• «^«in ""« on the outer face of the summer wood numerous, resinous, and prominent some times aggregated to form distinct and rather broad zones. Res nous the ra;!' °""'"^ '"'"" ^'''"P'* °^ "'"^' ''"'^^ '" ^°"«a" w1"h ^'^'^naVrJw^'rn^Sn'T'^f"'?''''/. '■"'"°""' throughout; the rav tracheids !k.,? ' "l'"^«"'^'' °^'l" '°""y wanting. Ray cells straight or some- what contracted at the ends, equal to 10-15 spring tracheids The ,h IT" rit'^'' ' ?""",«'y ?'"^^ ' "^'^ "PP'^'- ^"'l lower walls medium to Si ^f ^'Tg'y.Pi't^d, especially in the summer wood; the ateral walls with small, oval, at first narrowly bordered pits, the len' .cular ontice at length oblong, .-4, chiefly 2, per tracheid, becoming in the summer wood, where the orifice is a prolongs ' slit Bordered pits round or elliptical, chiefly somewhat distant in , row. Targe wnnd'Tf °"''" '"■«"• ^'*''°" ^"^^ »^"fe^"''^' walls of the ^umme; wood no very numerou.s, small, often remote and obscure. Resin cells on the outer face of the .summer wood 15-20 u wide, 1 1 c--'7c „ long, chiefly about 150 ^. Resinous tracheids sometimes locally numei.ius, the re.sin ma.ssive. ^ T,w^ential. Rays numerou.s, medium to high, .somewhat resinou.i ; the cells obbng-oval, more rarely oval, rather equal and uniform. Ray tra- cheids very few, terminal, very often wantin-. ^ m i 270 ANATOMY OF THE GYMNOSPERMS An Alpine tree rarely 3001. in height, with a trunk 1.50-2.10111. in diameter. Wood light, soft, not .strong, close grained, satiny, susceptible of a good polish. Relative specific gravity 0.4454 Percentage of ash residue 0.44 Approximate relative fuel value 44-35 CoeiTicisnt of elasticity in kilograms on millimeters . . 775. Ultimate transverse strength in kilograms 307. Ultimate resistance to longitudinal crushing in kilograms 6074. Resistance to indentation to 1.37 mm. in kilograms . . 1664. (Sargent) Dry slopes and ridges near the limits of tree growth, from 2700 feet in British Columbia to 10,000 feet in Colorado. Valley of the Fraser River, on Silver Mountain, Vale, and probably much farther north (Macoun); south along the Ca.scade Mountains and the California Sierras to the headwaters of the ^an Joaquin River ; ca.st- ward along the high mountains of northern Washington to the Caur d'Alene and Bitter Root mountair.s of Idaho, and the divide between Thompson and Little Bitter Root creeks in northern Montana (Sargent). S. T. Mertensiaoa, Carr. lyeslern Hemlock Transverse. Growth rings thin, the prominent summer wood dense and about equal to the spring wood, from which the transition is gradual. Spring wood very open, the large and thin-walled tracheids conspic- uously squarish, in very regular rows, uniform. Medullary rays vtry prominent, resinous, rather broad, i cell wide, distant 1-9 rows uf tracheids. Resin cells very prominent and resinous, sometimes form- ing short rows of imperfectly organized resin canals on the outer face of the summer wood. Radial. Rays uniformly somewhat resinous throughout, the tracheids verj unequal, short, sometimes obscure, not infrequently interspersed. Ray cells narrow, conspicuously contracted at the ends, equal to 4-9 spring tracheids ; the upper and lower walls medium, unequal, rather strongly pitted; the terminal walls coarsely pitted; the lateral walls with small, conspicuou.sly bordered oval pits with an oblong orifice, 1-2, rarely 3, per tracheid, becoming obscure Mn the summer wowl. Bordered pits round or elliptical in i row. Pits on the tangenti.il walls of the summer tracheids numerous but small and obscure. Resin canals composed of short, cylindrical resin cells, which unite to form disconnected passages. Resin cells very long and narniH, abovit 1 5 fL wide and 1 5c -385 (a. long. Tangent in I. Rays rather numerous, medium to high, resinous, ratlier broad, the somewhat thick-walled cells rather unequal and variable, round or oval. YX PSEUDOTSUGA 271 A large tree 30-61 m. high, with a trunk 1.20-3 m- in diameter. Wood light, hard, not strong, rather close grained. Relative specific gravity 05182 Percentage of ash re.sidue ! ! ! . o 42 Approximate relative fuel value . . 51.61 Coeflficient of elasticity in kilograms on millimeters , '. 1375. Ultimate tran-sverse strength in kilograms jgg] Ultimate resistance to longitudinal crushing in kilogram- 8747. Resistance to indentation to 1.27 mm. in kilograms . 1622 (Sarg.i.t) Low, moist bottoms and rocky ridges; very common and reaching its greatest development in western Oregon and Washingtc.i, often form- ing extensi-- forests (Sargent); valley of the Columbia at Donald, at 1000 feet elevation, .hence westward to Stony Creek at 3500 feet, .hence the predominant tree to the Selkirk summit (Macoun); Alaska, thence south along the islands and coast of British Columbia and through the Rocky Mountrns to the Bitter Root Mountains of Idaho; the western slopes of the Kocky Mountains of Montr.na ; through the Cascade Mountains of southern Oregon and the co:'.:it ranges to Marin County, California, between iock and 4000 fee' elevation (Sargent). 14. • PSEUDOTSUGA, Carr. Plates 46 and 47 Transverse. Growth rings and summer wood very variable. Resin pas- sages prominent and well formed without thylo.ses, but with thick- walled epithelium. Resin cells more or less numerous on the outer face of the summer wood, not very resinous, and usually distinguished by their (1) thinner walls and somewhat advanced position, and (2) by the sieve-plate structure of the terminal walls. Radial. Ray tracheids present. Ray cells with thick and coarsely pitted terminal walls. Wood tracheids always with flat and close spirals in double series. Tangential. Fusiform rays present, generally narrow, the central tract composed of i small resin canal without thyloses, but with small and thick-walled ep'-'-elium cells; the ray cells thick-walled throughout. Synopsis of Species Ray cells (tangential) distinctly oval or oblong. Pits on the lateral walls of the ray cells small, round or oval, at first 3-7, soon 1-3, per tracheid. 1 . * P. Douglasii. Ray cells (tangential) broad, distinctly squari.sh, more rarely oval or round. Pits on the lateral wal.s of the ray cells conspicuously larger than in I, the orifice lenticular, 3-6 per tracheid. 2. P. macrocarpa. ■'--TP 272 ANATOMY OF THE GYMNOSPERMS ft i Kay cells oval or round (tangential). Pits on the lateral walls of the ray cells 4 per tracheid. 3. •• P. miocena. 1. * P. DougUsii, Carr. Yellow Fir. Ortgon Pint. Douglat Fir Transverse. Growth rings very variable, and either very thin with a close, compact grain, or very broad with a coarse, open grain. Summer wood very variable, now barely distinguishable, or again upwards of one half the spring wood, often hard and flinty ; transition from the spring wood more or les.s abrupt. Spring tracheids large, thin-walled, hexagonal, uniform in regular rows. Medullary rays prominent and somewhat resinous, rather few, i cell wide, distant 2-13 rows of tracheids. Resin pa.s.sages rather few and widely scattering, chiefly in the summer wood, the canal equal to about i or 2 tracheids. Resin cells few and distant on the outer face of the summer wood, not very prominent or resinous, chiefly distinguished by their position and the sieve-plate structure of the terminal walls. Radial. Rays sparingly resinous throughout, the tracheids prominent, chiefly narrow and margi lal, but sometimes interspersed. Ray cells straight or somewhat contracted at the ends; the upper and lower walls thickish, irregularly and often imperfectly pitted ; the terminal walls coarsely pitted ; the lateral walls with small, elliptical pits, the border narrow, the orifice lenticular, at first 3-7, soon becoming 1-3, and in the summer wood 1, per tracheid. Pits on the tangential walls of the summer tracheids wanting. Resin cells 15-25 \k wide, 125-225 /t long. Bordered pits in 1 row, sometimes in pairs, gen- erally elliptical, the orifice large. Spirals generally wanting in the summer tracheids, the angle 82°. Tangential. Fusiform rays with linear and unequal terminals. Ordinary rays low to medium, the cells oval to oblong. Medullary ray cells all thick-walled. This species presents the most striking variationy of any of the North American ConiferaE. These variati 1. ns follows: 1. The growth rings occur in zone. aich there are pronounced differences in the average thicknet iponent rings (52). 2. The growth rings vary from s- ..meters in thickness to less than I mm. In this respect a distinciiou may be made between the " fine-grained," in which the rings seldom exceed 2-2.5 mm., usually beini,' much less, and the " coarse-grained " wood, in which the rings approx- imate to 4 mm. in thickness ; the latter is further distinguished by its coarse, open grain, and often very flinty summer wood, thus .ipproximat- ing to the " red fir," as represented by the next species. 3. The summer wood varies greatly, either in the same tree or in different trees, being in one case barely if at all distinguishable ; nr, on the other hand, becoming very prominent, dark, dense and tliiity, and often equal to the spring wood. PSEurx)T:Hc;A 273 4. The size of the trachcid.H and the volume of the lumen vary rela- lively to the total area of the cross section, whereby in some cases the summer wood presents a very dense structure, while in others it is com- paratively open. The extreme variations observed in nine specimens from different localiUes lie within the following limits : Spring wood .... ■,,,,-, ., ._ Summer wood . ,VJl '^ ~ i) " ^^ '^ A large tree 61-92 m. high, with a trunk upwards of 3.66 m. in diameter Wood hard, strong, varying greatly with age and conditions of growth! difficult to work, very durable (Sargent). Two varieties are recognized : the "yellow fir," di.stinguished by its lighter color and usually fine and compact grain; and the "red fir,' which approximates to the characteristics of the next species and is distin- guished by its darker red color, coar.se grain, and flinty summer wood The former is of superior quality for constructive purposes. The great strength and durability of this wood make it the mo.st valuable species of the Pacific region, and it is largely employed where these qualities, joined to great size of timber, are required. Relative .specific gravity Percentage of a.sh residue ....... i . ' Approximate relative fuel value Coefficient of ela.sticity in kilograms on millimetcr.s ! Ultimate transverse strength in kilograms Ultimate resistance to longitudinal cru.shing in kilograms Resistance to indentation to 1.27 mm. in kilograms (Sargent) 05157 0.08 5'-53 1283. 376. 8289. 1608. A comparison of these valu> ith those given by Sargent for .some of the more commonly u.sed oak will serve to show the superior quality of this timber, which has a hig.ier coefficient of elasticity than our three best native species. Comparative Strength ok Oaks and Pouglas Fir (After Sargent) I'seudotsuga Uouglasii White oak (Quercus alba) Ued oak ((^uercus rubra) live oak (Quercus virens) Coefficient of Elasticity in Kil- ograms on Millitneters 1283 97 1 "37 113O Cltimate Trans- verse StrinKth in Kitogra > 370 3.% 434 Ultimate Resist- ResisUnce to I ance to I,ongi- | Indentation tudinal Crushing to 1.17 mm. in I in Kilograms i Kilograms 8JS9 S.S3 .S.7.' 874S 1608 3388 2825 5185 [.W ill K 274 ANAIOMY OK IIIK (;VMM)SI'i:kMS According; to experiments reported by Dr. Bovey, as carried out in the teHtitiK laboratorieR at McGill University the following values may be ansiKned to Douglas fir : Specially selected wood, free from knots and cut out of the log at a distance from the heart, gave Coefficient of bending, pounds per square inch . . 9iOOO Coefficient of elasticity in pounds 2,000,000 Weight per cubic foot 34 Ordinary fiist-quality wood gave Coefficient of bending, pounds per square inch . . 6,000 Coefficient of elasticity in pounds 1,430,000 Weight per cubic foot 34 The Douglas fir often forms extensive forests to the almost complete exclusion of other species, ranging from sea level to an elevation of nearly 10,000 feet in Colorado, and reaching its greatest development and value in Oregon and Washington (Sargent). All parts of Vancouver Island with the exception of the exposed western coa.st ; near the 49th parallel it ranges from the coast of the mainland to the Rocky Mountains, where it occurs in a stunted form at eleva- tions of 6000 feet ; on the eastern slopes of the Rocky Mountains, from the 49th parallel northward through the Porcupine Hills to the Bjw RiviT, where it reaches its eastern extension at Calgary; in the interior of southern British Columbia it is generally confined to the higher uplands between river valleys ; northward it de.scends to the general level of the country (Macoun); mountain ranges of Washing- ton, Oregon, and the California coast ranges and the sierra Nevadas; east to Montana, Wyoming, Colorado, and the Guadeloupe Moun- tains of northern and eastern Arizona, and '^'uhward into Mexico (Sargent). This tree is known out sparingly in the fossil s. , the only representa- tive so far known having been derived from the glacial deposits at Mystic Lake, near Bozeman, Montana. The age of these deposits cannot be accurately determined from the present data, but they proi)- ably represent the result of glaciation which may have continued for some time after the period of continental glaciation, and even until quite recently. The tree is, however, now extinct in that locality, and it is possible that its elimination may have been due to the same general cau.ses that brought about a withdrawal of Sequoia from the prairie region during glacial time. PSEUDOTSUGA j^j 8. P. nuKTocarpa, Mayr. Iltmtott Trannfene. Growth rings broad, variable, the denM nummer wnnrf ,.«-. po^ed of rather nmall. rounded tracheidn in ir^^^rr rows Coward; of one third the spring wood, from which the trans tionii S.l Spring tracheids rathe, ■ irge and squarish-hexagonal thT Ss mediun, rather uniform in regular rows. MedujfarJ ays prom nent and resinous, numerous and wide chieflv i r,Ai la ].""" .-f. rows of tracheids. Resin paTsrKe^numl'sLTT'M ''■""• equal to al>out . tracheid. Resin' cellf n^:ruTand'"p omSl' he outer face o the summer wood, and at once rtcognTzable bv their color, position, and structure. Resinous trach^iH. Jf!. .^ ^ P^sent and forming small group, or radTa^^^^Lri^^S.'acTwiVhTh: RadiaJ. Rays sparingly resinous throughout, the tracheids narrow mar- g^nal, or some imes interspersed. Ray cells straight or conUac'ted i theend.s, equal to 6-10 spring tracheids; the upper and lower will! medium sparingly pitted except in the summer wood -the terminal wa Is chiefly rather thin and not very strongly pi„ed the aTra walls with prominent and re,, nous pits conspicuL.r much lar Je han in P. Douglasii, the border prominent, Ihe orifice^" first ifn ticular at length oblong, at first 3-6 throughout the spr nt wJoS" BoX/h' ^^r^'^^ ''^"•^^'' '" ' ^' '"•^'^^■^ ■" 'he summ"'; wood Bordered pits numerous in i row, strongly elliptical. Fits on the ReTn" S ""'•" "f ••'^''"•""'".j'acheids f^^^ ver/small and obscure' Resin cells upwards of 50 ^ wide and 135-300 ^ long. Spirals more or less obscure, often distant, finally vestigial and in the .«uZer wood wanting, the angle 70°. u"i"icr Tangential. Fu.siform rays lenticular or the terminals unequally linear narrow, the central tract with , small resin ,nal. Ordinar ra>^ sometimes 2-seriate in part, resinous, broad, medium to high- the or n.!'„H'" «"^' ""T^'' """^ ""'f°'"'' '^q"^"'*'^' ■^of'^ rarely oval or round. Rays much more numerous than in P. Uougla.xii. A tree 30-54 m. in height, with a trunk of 1.08 m. in Hiameter Wood heavy, hard, strong, cross grained, very durab! difficult ,■■ work. Relative specific gravity . . ojt*» Percentage of ash residue ...'.'.".;" " 008 ' Approximate relative fuel value 45 'q Coefficient of elasticity in kilograms on millimeters '. '. 1050 ' Ultimate tra-'sverse strength in kilograms ... 361 Ultimate resistance to longitudinal crushing in kilogams 740c Resistance to indentation to 1.27 mm. in kilograms . 164^ (Sargent) "*"■ Ury ridges and cafions between 2500 and 4000 feet elevation; the coast ranges of California; San Bernardino Mountains to the Ciyamaca Mountains (Sargent). f ^ 1 np» 376 ANATOMY OF THE GYMN'OSPFRMS I II 11 11 I. * * P. mloeMM, i'enh. TVwNJtyM. Growth ringt broad and prominent ; the tracheidn of the *prini; wood large and thin-walled, the structure passinK ((radually into the thin but rather prominent summer wood composed of about 3-10 rows of thick-walled trailieid*. Kesin cells net obvious. Kesin passa^eM •mall, not very numerous, chiefly in the summer wood, often double, as in P. Douglasii ; the epithelium cells small and thick-wallea. Medul- lary rays slightly resinous. The entire structure of the transverse section bears a strong resemblance to the fine-grained wood of P. Uouglaaii. Radial. Bordered pits in i row. Cells of the medullary rays straight, thu thin upper and lower walls devoid of pits. Pits on the lateral walls of the ray cells about 4 per tracheid. TaHgtHtial. Ordinary rays i -seriate or 2-scriate in part, the cells oval or round, thick-walled, about 24.5 ^ broad. Fusiform rays narh>w, the cells thick-walled, the resin canal narrow. Material silicified or preserved in the natural state. Eocene of the Great Valley and Porcupine Creek groups, Saskatche- wan ; Miocene of Cariboo, British Columbia. 18. * LARDE, TouRN. Plates 48 and 49 Tranmerse. Summer wood prominent, u.sually dense, the transition from the spring wood more or less abrupt. Kesin passages without thy- loses but with thick-walled epithelium. Re-sin cells .somewhat frequent, but scattering on the outer face of the summer wood. Radial. Ray tracheids prominent, sometimes interspensed ; the terminal walls of the parenchyma ray cells thick and strongly pitted. Bor- dered pits in I or 2 rows. Tracheids wholly without spirals. Tangential. Fusiform rays prominent, usually high and narrow, the cells small and thick-walled, the resin passage usually small. Cells of tlie ordinary rays oval to oblong. A well-defined genus, at once distinguished by the narrow and usually hJKii fusiform rays, the resi , cells scattering on the outer face of the summer wood, and the absence of spiral tracheids. Lt * Synopsis of Species Bordered pits in 1-2 rows. Pits on the tangential walls of the summer wood not confined to tiie outermost tracheids. Pits on the lateral wall.-, of the ray cells 2-6 or 8 per tracheid. Ray cells (tangential) rather unequal, .sometimes in pairs, somewhat variable, oval or oblong. I. L. occidentalis. I.ARIX 277 FilM on the tangenUal w.ills ,>( the siimmrr wood confined to ih<; outcrrnnttt traihcid. FiU oti tliL lateral « il|>. ,,f the ray ctlU i-f, per tra« ;uid. Ray celU (i,, ,'ential) equal, uniform, and < ..lonj,', more rarely oval. 2. • !.. americana. Bordered pita In i row, nometimes In pairs. Fits on the tangential walls of the summer »ood confii.ed lo '.r.e outermost tracheid. Pits on the lateral walls of the ray cells 3-6; those on the tan- ((cntial walls of the summer wood numerous and small. Kay cells (tangential) equal ai.J very uniform, narrowly oblon/r. Ivallii. Pits on the lateral walU ' 1., ray cells 2-6 per tracheid; those on the tangential walls ine summer wood few, small, con- fined to the outermost wall. Ray cells (tangential) oblong, more rarely oval, ai.d much broader. 4. L. leptolepi.H. 1. L. occidenUUi, Nutt. Tamaraci Tratuverse. Growth rings usually broad, the dense and prominent .sum- mer wood about one half the spring wood, from which the transition IS abrupt, Tracheids of the summer wood large, squari.sh, in regular rows. Tracheids of the sprirn,' wood very large and thin-walled, squarish-hexagonal, in very regular rows, rather uniform. Medullary rays prominent, rather resinous and broad, i cell wid-, distant 2-6 rows of 'acheids. Resin pas.sages few, large, witho- thyloses, the epitheh arrow, rather thin-walled, the nutritive layer thick-walled resinous .esin cells widely scattering on the outer face of the ,ummer .v,od, but readily recognized by their abundant resinous confi nts. A'«i.u'. Kays conspicuou.sly resinous throughout; the tracheids narrow !.i. marginal, rarely interspersed. Ray cells chiefly straight through- '■M' and equal to 3-9 spring tracheids; the upper and lower walls chiefly thick and unequal, sparingly pitted throughout, more strongly so in the summer wood ; the terminal walls coarsely pitted throughout ; the lateral walls with elliptical and distinctly bordered pits, with a narrow, chiefly oblong or lenticular orifice, numerous, at first 6-8 per tracheid, soon greatly reduced in size, and in the summer wood abruptly i per tracheid. Bordered pits conspicuously in 1-2 rows, more rare y in I row only, elliptical, the orifice very large. Fits on the tangential walls of the summer wood rather numerous but small and often obscure. Resin cells about 12 ? u wide and 60-150 u long. 278 ANATOMY OF THE GYMNOSPKRMS Tiuij^eiilial. Rays rather numerous, low to very high. Fusiform rays with a large resin canal without thyloses, the epithelium cells thick-walled. Ordinary rays often very high, chiefly very uniform, and not con- tracted at the position of the rarely intersf)ersed tracheids ; the paren- chyma cells rather unequal, sometimes in pairs, oval or oblong, somewhat variable. This species appears to be more or less variable according to local con- ditions of growth. From low elevations sp>ecimens appear to exhibit little variation, but from high elevations (Mt. Higgins, Montana, altitude 8700 feet) they present very well-defined structural deviations. These ■ ppear chiefly in the much narrower and unequal growth rings. A ree 30-45 m. high, with a trunk upward of 1.50 m. in diameter. Wood heavy, exceedingly hard and strong, rather coarse grained, com- pact, satiny, susceptible of a fine polish, very durable in contact with the soil, and of great economic value. Relative specific gravity 0.7407 Percentage of ash residue 0.09 Approximate relative fuel value 74. Coefficient of elasticity in kilograms on millimeters . . 1658. Ultimate transverse strength in kilograms 524. Ultimate resistance to longitudinal crushing in kilograms 11,023. Resistance 10 indentation to 1.27 mm. in kilograms . . 2395. (Sargent) Abundant in the Ki ■ .tenai-Columbia valley of British Columbia (Macoun) ; through the mountain ranges of northern Washington to the western slopes of the Rocky Mountains of Montana ; the Blue Mountains of Washington and Oregon ; moist mountain slopes and benches between 2500 and 5000 feet elevation ; scattered among other trees, never form- ing separate forests (Sargent). 2. L. americana, Michx. Larch. Black Larch. Tamarack. Hackmatack Transverse. Growth rings rather broad and uniform, sometimes double. Summer wood rather dense, about one fourth to one half the sprini; wood, from which the transition is either gradual or abrupt, the tracheids small, conspicuously unequal and not in very regular rows, distinctly rounded. Spring tracheids large, hexagonal, radially eloii gated, thin. Medullary rays prominent, broad, 1 cell wide, distant 2-8, rarely more, tracheids. Resin passages large, equal to 2-3 tracheids, devoid of thyloses ; the epithelium cells flat, rather thin- walled ; the nutritive parenchyma scanty, thick-walled ; not very numerous, chiefly in the summer wood. Resin cells few, widely scat- tering on the outer face of the summer wood, nonresinou.s, distin- guished by (1) their thinner walls and advanced position, and (2) by the sieve-plate structure of the terminal walls. LARIX 27^ Radial. Rays somewhat resinous throughout ; the trarhcids np.niin.nf con's .^"Ih:"*^'"^'- ''--^'^>-^ "y cclL"statht''o;" d : uneS ,nd ''i^,';"'"'^" .^^'^^ ; the upper and lower walls thick. DittPH^L K \ ^ sparingly pitted; the terminal walls coarsely mo . .,"S =- T"""' '"»"• »PP'"™«'-. on "£ ou e " most tracneids only. The outer summer tracheids often show a aruM.rX' '° "' '''™^"°" °^ ^'''^^'^- «-^<" ""'-^ M -^e! ^''"S£rm^?vs"whhTh• '"^"'"^high. sparingly resinous. The lusiiorm rajs with a broad central tract and a larue resin nn-.l mo?e rarefy oyil "j^f «'""^*»' ':'''^">- "'h" equal, uniform, oblong. nTr"ow"a"d^n7eipeS^r^h:;^s^• '''"'"^'^'^ ^' ''^^ ''°'^'''«" °^ ''^ A tree 24-30 m. high, with a trunk upwards of .90 m. in diameter. Wood heavy, hard very strong, rather coarse grained, compact, durable in contact with the soil. Relative specific gravity Percentage of ash residue ." °-^^36 Approximate relative fuel value r°^| nm^'!'"!***''^''''''y'"''"°Sramsonmillimet'ers ] '. .^g'" U timate transverse strength in kilograms ,aj Ultimate resistance to longitudinal crushing in kilograms 876T (Sa"rgeSr *° '"^^ """" '" '''Wams^ . . .ers! Cold wet swamps, often covering extensive areas, or northward on moist uplands and intervale lands. This tree, together with the black spruce dominates nearly all the swampy land from Newfoundland, Labrador, and he eastern provinces of Canada to the Rocky Mountains; northward to latitude 6s°, where it is reduced to a height of 6-8 feet (Macoun)- southward through the northern United States to northern Pennsylvania' northern Indiana, Illinois, and central Minnesota (Sargent) A well-defined, widely distributed, and common tree in the Plei.stocene and more recent deposits, where the remains are preserved in a natural state, and often most perfectly. Leda clays, Montreal; Scarborough Heights, Ontario; Moo.se River. Ontario; Lower Till of Fort Madison. Iowa; Ithaca. New York; Don valley. Toronto; the black clays of the Columbian Formation (equiva- ent to Pleistocene of northern localities) at Dahlonega. Georgia; peat bogs of New Brunswick. s , v •^^ 28o ANATOMY OF THE GYMNOSPERMS % 3. L. LyallU, Pari. Tamaraci. Mountain /.iirch Transverse. Growth rings narrow, variable. The summer wood prominent and dense or sometimes open, equal to about one half to one third the spring wood ; the tracheids in regular rows, very unequal, small, radially narrow and rounded. Spring tracheids rather large, squarish- hexagonal, thin-walled, very uniform in regular rows. Medullary rays prominent, not very broad, i cell wide, distant 2-8 rows of tracheids. Resin canals not very numerous, small and widely scattering, devoid of thyloses, the epithelium not very narrow, thick-walled, Ihe nutrient parenchyma obscure or wanting. Resin cells somewhat numerous, slightly resinous and easily distinguished. Radial. Rays sparingly resinous throughout,the tracheids rather numerous, marginal, sometimes interspersed. Ray cells very stro'--ht through- out, equal to 3-7 spring tracheids ; the upper and lower walls thick, somewhat conspicuously pitted ; the terminal walls coarsely pitted throughout ; the lateral walls with numerous small, oval, distinctly bordered pits with an oblong, narrow orifice, 3-6 per tracheid, in the summer wood abruptly reduced to I. Bordered pits in 1 row, often in pairs, elliptical, large. Pits on the tangential walls of the summer wood rather numerous but small, and confined to the outermost tracheid wall. Resin cells few, 15 |4. wide, 110-155 /i, chiefly about 125 /I, long. Tangential. Rays rather numerous, low to high, somewhat resinous. Fusi- form rays very narrow and variable in height; the narrow and linear terminals often very unequal ; the cells all thick-walled ; the re.sin C.I rial small, usually narrow and oblong, often much reduced and nearly obliterated. Ordinary rays more or less 2-seriate in part, narrow, the cells very equal and uniform, narrowly oblong. Alow, straggling, Alpine tree, rarely exceeding 15 m. in height, with a trunk upwards of 1.50 m. in diameter. In the Rocky Mountains of Washington and Montana (Sargent); summit of South Kootenai Pass ; from Cascade Mountain, Bow River Valley, westward ; forming the last belt of timber on all the peaks of the Rocky Mountains, and ranging from 6000 to 7000 feet elevation ; growing with Pinus albicaulis (Macoun). 4. L. leptolepis, Gordon Jap. = FtijimatsH Transversa Growth rings rather broad. The very prominent and dense summ r wood composed of very angular and unequal tracheids in irregu.ar rows ; nearly equal to the spring wood, from which the tran- sition is abrupt. Spring tracheids large, thin-walled, very uniform in regular rows. Medullary rays prominent, I cell wide, distant 2-10 rows of tracheids. Resin passages not numerous, somewhat widely scat- tering, chiefly in the summer wood, the epithelium rather thin-walled, ,3" PICEA 281 the nutritive parenchyma thick-walled ; equal fo 1-2 tracheids, devoid of thyloses. Resin cells on the outer face of the summer wood few. dKslant ; recosnized by their thin walls and more advanced position, and the sieve-plate structure of the terminal walls. RadMl. Rays somewhat resinous throughout, with prominent, chiefly nar- bTJ II ** numerous, marginal tracheids, rardy interspersed. walU r^i h^^K^'^^^^'i^ •"'"Is*'' throughout; the upper and lower verl Jrn I •» •/* 1'"* """^ sparingly, but in the^mmer wood very strongly, pitted; the terminal walls coarsely pitted throughout ; ♦^.^1, ^'■^«*^"'/'u '**,''" ""^alLoval, bordered pits, with a lenl S Rnrn'' ==/'.f '"P"y "-^^duced to ,, per tracheid in the summer wood. Bordered pits very large, with a large oval orifice, elliptical, numerous, and often compact, two thirds the width of the tracheid Ui™"'"fi ^i'* ""♦•'« tangential walls of the summer wood few small confined to the outermost tracheid wall. Resin cells i? a wide 1 10-265 /* long, chiefly about 125 ^. 3 f* *=. Tangential. Rays rather numerous and resinous. The fusiform ravs wtiu J' ^'^ ""*' *'"'"' *'ti!0"t thyloses, the epithelium rather thick- Ap ini^rPn /VT •T**'"J" '° '*'«''• <=°"tracted at the position of unlfaTnl. *"•=''*'*•«' tl"^ parenchyma cells chiefly equal and uniform, oblong, more rarely oval and broader. 16. •PICEA, Link. Plates 50 and 51 Transverse. Growth rings variable, the transition to the usually prominent summer wood gradual Resin passages with or without thyloses, but wthth.ck-waUed epithelium cells. Resin cells wholly wandng. Radial. Ray tracheids conspicuous, chiefly narrow, marginal, or some- Z^H ' Trr/'-'.''- Terminal walls of the ray cells usually strongly pitted. Tracheids wholly without spirals Tangential. YyxsAiorm TT^ys chiefly narrow, with linear and often very unequal and much-prolonged terminals; the cells small and thick- h,f 111 t>.^ central tract of , small resin passage without thyloses more rardy ova? ^P"^'^''"'"- Cells of the ordinary rays oblong. This genus is readily distinguished from Larix and Pseudotsuga by the absence of resin cells and of spiral tracheids. Synopsis of Species Ray cells (tangential) variable, round, oval, or oblong. Pits on the tangential walls ot the summer wood chiefly or wholly confined to the outermost wall. Pits on the lateral walls of the ray cells 1-3 per tracheid. Ray cells (tangential) equal. Spring tracheids rounded-hexagonal, the structure not very open. 10. P. sitchensis. 282 ANATOMY OF THE GYMNOSPERMS 11 3 if.' Pits on the tangential walls of the summer wood few, often widely scattering; and extending for some distance into the summer wood. Pits on ihe lateral walls of the ray cells 2-6, chiefly 4, per tr.i- cheid. Ray tells (tangential) conspicuousl) unequal. Spring tracheids large, thin-walled, uniform in regular rows, squarish-hexagonal. 6. P. polita. Ray cells (tangential) usually very equal and unifor.n, oblong or oval. Pits on the tangential walls of the summer wood chiefly or wholly confined to the outermost tracheid wall. Pits on the lateral walls of the ray cells 2-4 per tracheid. 7. P. bicolor. Pits on tht. lateral walls of the ray cells 2-6 per tracheid. 3. • P. alba. Pits on the tangential walls of the summer wood not confined to the outermost wall, but chiefly small and inconspicuous. Rays (radial) nonresinous. Pits on the lateral walls of the ray cells at first narrowly bor- dered, 2-5 per tracheid, in the summer wood reduced to t. Ray cells (tangential) rather *hick-walled. Spring tracheids -oundec -hexagonal ; the summer wood rather open but piominent, upwards of one half the spring wood. 4. P. Engelmanni. Pits on the lateral walls of the ray cells with an oblonj; orifire, 2-6 per tracheid, toward the summer wood reduced to 2, and finally to I . Ray cells (tangential) thin-walled. Spring tracheids hexagonal, very thin-walled ; the summer wood very thin and open, often barely distinguishable. 8. P. pungens. Rays (radial) locally resinous, the resin chiefly confined to the thicker-walled and more strongly pitted cells, more rarely dif- fused throughout the central cells. Pits on the lateral walls of the ray cells with a ienticuiar orifice, at first 2-6 per tracheid, more rarely 2 throughout, in the suminer wood reduced to 2, and finally to i. Spring tracheids squarish -hexagonal, not very uniform, the walls rather thin. 9. • P. nigra. A, PICEA 83 Pita on the lateral walls of the ray cells with an oblon • narrow orifice, 3-S per tracheid, in the summer wood reduced to 2, and Anally to 1. Spring tracheids large, squ?rish-hexagonal. very unequal in regular rows, the walls thin. C , j*^ i' aOCFISIS Pits on the lateral walls of the ray cells with a narrow, oblong orifice, at first sometimes upwards of 7 per tra- cheid, soon 2-4, and in the summer wood 1-2. Spring tracheids large, squarish, very uniform in r gular ^ows, the walls rather thin. 2. P. rubra. Pits on the lateral wall, of the ray cells with a narrow, oblong orifice, becoming much extended in the summer wood ; 2-3, more rarely 4, per tracheid, becoming i in the summer wood. String tracheids distinctly hexagonal, conspicuously unequal in regular rows, the wi Is not very thin. ' P. Breweriana. 1. P. Bre^«reriaiu, Wats. IVeeping Spruet Transverse Growth rings rather thin and uniform. Summer wood rather th>n, of about .0-16 tracheids, prominent, not verHen^X ,„„ ri"rrT. **•' '""■"« r'^ «"''"^'' 'he tracheiSs unequa Tn ^fn.H l^ 'T'' "'"''"y ■"""^'^ compressed. Spring tracheids dii^ tinctly hexagonal, conspicuously unequal, in regular fows the wait not very thm. Resin passages rather numer. ;sfscatter7n; oft^n i^ small groups, and more or less imperfectly forced -he epiSirum .n 1-2 rows of very variable but thick-walled, often resinous ce^ ottracheTds""' ''™'"""'' '■"'"°"^' *^'="'' ^-«' --«= ^^^^^Cro^. ^'"*Y;,i^Kr'''t!;!"^'y.'"T°"''' ^^^ "y tracheids marginal. Ray cells •straight or becoming fusiform in the sumner wood, equal to 6-7 ireTJllSUfhir""'' r^"^ '^"^^^^'y pitted, 'the^^upp^r a'^d' ower walls rather thick, u-iequai, more or less obscurely pitted exceot ound TT\ T*^ ' 'u" '"'"=" ^^''^ ^•«»' conspicuously Ordered ZZtk^ T P"^'*'"^ ^" o>>Iongorilicewhichbecomes much ex in tJe'sim^nerToo^^f V'T^ "^^'^ ^^ ^' ''^^"^^^^ b*"""""? in " low SLT P-, '^T^ ' numerous, often much crowded, r^.L? ' ^""P""'- P"s on 'i'e ts .ial walls of the summer wood rJ^^al Tv""""'' ""' ""^"'"^ '° " ^*"'"°''' tracheid wall lllfi^X '^^r'^^^^ ^""'"°"«' "'^'l'"'" "> high, not are^Ivnv^f ' p ■*""* chiefly equal and uniform, oblong, or more mucLVr^.jingl^d"""""^""'*'" few. narrow; the termLls often 284 ANATOMY OF THE GYMNOSPERMS V lit A tree upwards of 30 m., or more rarely 36 m. in height, with a trunk .60-.90 m. in diameter. Wood soft, close grained, compact, with a satiny surface. 0.5141 Relative specific gravity (Sargent) This tree oc ars m small, scattered groves in the elevated mountain regions of California and Oregon, Ltiween 4000 and 7500 feet altitude (Sargent). 2. P. rubra, Dietr. XtJ Sfruce Transverse. Growth rings narrow, rather variable. Summer wood narrow, not very pn.minent, upwards of 10 tracheids, rather open; the tran- sition from the spring wood gradual. Spring tracheids rather larg , hot very thin-walled, in very regular rows and very uniform, squari.sh. Resin passages widely scattering, not numerous, medium and equal to about 2 tracheids ; the epithelium composed of rather small, thick- walled cells ; wholly devoid of thyloses. Resin cells wholly wanting. Medullary rays 1 cell wide, not numerou.:, or prominent, distant 3-14 rows of tracheids. Radial. R?>s sparingly resinous, the resin usually localized and more or less confined to the thicker-walled and more strongly pitted cells ; the ray tracheids prominent, marginal, rarely interspersed. Ray cell.s straight throughout, or barely fusiform in the summer wood, equal to about 5-7 spring tracheids; the terminal walls strongly pitted; the upper and lower walls rather thin, distantly and obscurely pitted, or in the summer wood more or less strongly pitted ; the lateral wa!'s with small, elliptical, bordered pits with an oblong orifice, at fir-, sometimes upwards of 7 per tracheid, soon 2-4, and in the summer wood 1-2. Bordered pits broadly elliptical or round, in 1 row, not crowded, but variable in size. Pits on the tangential walls t' the summer wood very small and much compressed. Tangential. Rays somewhat numerous, medium, sparingly resinous. Fusi- form rays narrow, the resin canal small with thick-walled epithelium. Ordinary rays not broad, medium, the eel! very equal and uniform, oblong, or sometimes oval throughout. A tree usually 21-24 m., and occasionally 30-33 m. in hei^'it, with a trunk .60-.90 m. in diameter. Valley of the St. Lawrence and the northern shores of Prince Edward Island, southward through Quebec, the Maritime Provinces, and along the Atlantic coast to southern Maine and Cape Cod ; through the hilly interior and the mountainous parts of New England and New York, thence along the Allegheny Mountains to the high peaks of western North Carolina (Sargent). PICKA 285 3. • P. attM, Ait. Wtrtr Spruct Thtmsvtrte. Growth rings thick. Summer wood thin, rather prominent f^l'^tf °"1 ^T^ the Hpn'ng wood from which the'^Ston is gradual, rarely abrupt ; the structure rather dense ; the tracheids conspicuously squarish. Spring wood open, the tracheids squarish' hexagonal, uniform in very regular rows, the walls thin. Resin pas- sages scattering rat.ie. large, round, commonly without thyloses and .-ather thm-valled cells. Medullary ray.s not very numerous rather prominent, narrow. . cell wide, distant 2-14 rows of tracheids /ladui/. Rays very daringly resinous; the ray tr. cheids prominent, mar^ ginal. somet"..es interspersed in the higher rays. Ray cells straight throughout, equal to 5-1 3 .spring trachHds ; the terminal walls coarsdy p.t ed ; the upper and lower walls rather thin, unequal, sparingly pitted •n he spring wood, strongly pitted in the summer wood ; the lateral walls with numerous small, oval pits with a lenticular orifice. 2-6 per tracheid, in the summer wood abruptly reduced to 2, and finally to 1 Bordered pits in i row, numerous, round.or elliptical, the orifice large ; in the summer wood becoming r. mote and finally obscure, the orifice usu- ally a prolonged slit. Pits 01. the tangential walls of the summer wood very flat and obscure, chiefly confined to the outermost tracheid wall langenttal. Rays rather numerous, nonresinous, low to hiL'h Fusiform rays narrow, the cells thin-walled, the resin canal small, the epithelium composed of thick-walled cells. Ordinary rays narrow, not conspic- uously contracted by the occasionally interspersed tracheids ; the cells very equal ana uniform, oblong, narrow. A tree 15 50 m. high, with a trunk upwards of .90 m. in diameter. Wood light, soft, not strong, close and straight grained, compact, satiny. Relative specific gravity 040C1 Percentage of ash residue . o 12 Approximate relative fuel value ........' 40 38 Coefficient of elasticity in kilograms on millimeters .' .' io'3 Ultimate transverse strength in kilograms 3,0 Ultimate resistance to longitudinal crushing in kilograms 5480 Resistance to indentation to 1.27 mm. in kilograms 1117 (Sargent) According to Bovey the following data have been obtained : Coefficient of strength in pounds for ; S*^"*^.'"*: Sooo To^s'on 9000 Compression \^^^ Shear .^ Weight of I cubic foot ........... 30 N'ewfoundland. Anticosti, Nova Scotia, and New Brunswick, westward through Quebec and Ontario to the forest limit of Manitoba ; in the i& I 386 ANATOMY OF THE GYMNOSPERMS P 5»r prairie region being found in the sand hills bordering the first prairie steppe. Occasionally in the valley of the Saskatchewan and on the Bow River fr:. . Calgary, where it is mixed with P. Engelmanni ; on the Athabasca to latitude 54° 7' 34" (Macoun). Coast of Maine through northeastern Vermont and westward through northern Michigan and Minnesota to the Bla'k Hills of Dakota ; along the Rocky Mountains of Montana, where it reaches its greatest development along streams and lakes in the Flathead region, at elevations of 2500-3500 feet (Sargent). Pleistocene of the Scarborough period of which it is characteristic, at Scarborough Heights, Ontario. Material preserved in the natural state, but showing the efiects of exten- sive decay. 4. P. EngelBUUiiil, Engelm. IVAiU Spruct. Engtlmann's Spruct Tranwerse. Growth rings broad. Summer wood very prominent and rather open, about one half to one third the spring wood, from which the transition is gradual ; the tracheids often much compressed radially. Spring tracheids rounded-hexagonal, unequal in regular rows, the walls thin. Resin passages without thyloses, not very numerous ; the epithelium cells very unequal, rather thin-walled. Medullary rays not very prominent, n.« -row, i cell wide, distant 2-7 rows of tracheids. Radial. Rays nonresinous; the ray tracheids prominent, marginal. The ray cells generally straight and equal to 7 spring tracheids ; the ter- minal walls strongly pitted ; the upper and lower walls medium and sparingly pitted, except in the summer wood ; the lateral walls with small, oval, and at first narrowly bordered pits, 2-5 per tracheid, in the summer wood gradually reduced to i. Bordered pits in i row, large, not very numerous, round or elliptical, the orifice finally becom- ing a prolonged slit upwards of 34 ;*. Pits on the tangential walls of the summer wood small and not prominent, chiefly confined to the outermost wall. Tangential. Rays rather numerous, medium to high, nonresinous. The fusiform rays rather broad, the resin canal large and round, with thick-walled epithelium. The ordinary rays rather narrow, the cells very equal and uniform, narrowly oblong, rarely broader. A large tree 24-26 m. high, with a trunk upwards of 1.20 m. in diameter. Wood very light, soft, not strong, very close and straight grained, com- pact, satiny. Relative specific gravity 0.3441) Percentage of ash residue 0.32 Approximate relative fuel value 33. 3*5 Coefficient of elasticity in kilograms on millimeters . . 808. Ultimate transverse strength in kilograms 245. Ultimate resistance to longitudinal crushing in kilograms 4271. Resistance to indentation to 1.27 mm. in kilograms . . 5217. (Sargent) I'ICEA 287 This tree characteriw.H the interior plateau of Uritish Columbia, with the exception of the dry southern portions, forminx dense Krovcs in the mounuin*. It ranges northward to latitude 54^ 7-34- at an altitude of 2600 feet (Macoun). Dry gravelly ridges and slopes between sooo and 11,500 feet elevation, constituting the most valuable timl)er tree of the central Rocky Mountains, where it forms extensive forests, generally above 8500 feet elevation. Rare and of small size in the mounuins of Washington, Oregon, and MonUna (Sargent). ». P. J«soeiisi>, Carr. ya/>. = rsAi Transi'trse. Growth rings narrow, uniform. The very thin summer wood open and composed of 5-10 tracheids. about one fourth the spring wood, from which the transition is rather gradual. Spring tracheids large, squarish-hexagonal, thin-walled, very unequal but in reirular rows. Resin passages not very numerous, chiefly large, with thyloses. the epithelium of very unequal, rather thick-walled cells. Medullarv rays not numerous, rather resinous and prominent, 1 cell wide dis- tant 2-8 rows of tracheids. A'afiia/ Rays sparingly and locally resinous; the ray tracheids prominent and often interspersed. Ray cells somewhat contracted at the ends equal to 3-7 spring tracheids ; the terminal walls coarsely pitted the upper and lower walls not very thick, conspicuously pitted, espcciallv in the summer wood ; the lateral walls with small, oval, bordered pits with a narrow orifice, 3-5 per tracheid, in the summer wood reduced to 2, and finally to 1. Bordered pits large, strongly elliptical, in 1 row rather numerous, often in compact rows towards the ends of tracheids Pits on the tangential walls of the summer wood rather few. small' and inconspicuous. ' ' Tangential. Rays not very numerous, low to medium, sparingly resinous Fusiform rays rather broad, the rather large resin canal with thick- walled epithelium, chiefly without thyloses. Ordinary rays not very broad, contracted at the position of the sparingly interspersed tra- cheids ; the cells rather thick-walled, very equal and uniform, narrowly oblong, rarely oval. ' 6. P. poliU, Carr. _/<;/. = Iramomi Tram'"erse. Growth rings thin, very variable. Summer wood prominent rather dense but variable, from 3 tracheids thick upwards, equal to one half to one third the spring -vood from which the transition is rather gradual ; the tracheids variable. Spring tracheids rather large and thm-walled, uniform in regular rows. Resin passages rather numerous, large but variable, equal to 1-4 tracheids, with thylo.ses- the epithelium of very unequal, rather thin-walled cells. Medullary rays rather numerous and broad, i cell wide, resinous, distant 2-8 or 10 rows of tracheids. ^1 a. i 388 ANATOMY OF THE GYMNOSPERMS Radial. Ray* locally very resinoua throughout; the ray tracheids low, unequal, marKinal, Homctimes InteraperMd. Ray celli more or leu contracted at the ends, eapecially In the Rummer wood, equal to 7-8 •pring tracheids; the terminal walls thin, often locally thickened or sparingly pitted, sometimes entire ; the upper and lower walls thicker and strongly pitted in the resinous cells, thinner and sparingly pitted in the nonresinous cells ; the lateral walls with small, oval, Dordered piu, the orilice narrow, oblong, 2-6, chiefly 4, per tracheid, in the summer wood rather abruptly reduced to 1. Borde.ed pits numerouH, elliptical, in 1 row, sometimes in pairs. Fits on the tangential walls of the summer wood rather few and no; very prominent, flat, often widely scattering, and extending for some distance into the summer wood. Tanjitntial. Rays numerous, low to high, rather broad, resinous. The fusiform rays rather narrow, with a small resin canal and thick-wallcd epithelium. Ordinary ravs contracted at the position of the occa- sionally interspersed and -ery narrow tracheids ; the parenchyma cells conspicuously unequal and variable, from round or oval to oblong, often narrow and high. % 7. P. bicolor, Mayr. Jap. = OTShi Tranmerst. Growth rings narrow, uniform. The narrow summer wood of 6-10 tracheids, about equai to one third to one half t1>e spring wooti from which the tran.sition is rather gradual ; not very dense, the tra- cheids much flattened and rounded. Spring tracheids conspicuou.sly squarish, thin-walled, uniform in very regular rows. Resin passages rather large, often with thyloses ; the epithelium composed of very unequal, thick-walled celLs. Medullary rays rather prominent, some- what resinous, i cell wide, distant 2-10 rows of tracheids. Radial. Rays somewhat resinous, the resin localized; the ray tracheid.s numerous, prominent, and marginal, often interspersed. Parenchyma cells straight, equal to about 8 tracheids ; the terminal walls thin, at first sparingly, soon strongly, pitted throughout ; the upper and lower walls medium, very sparingly pitted, or again thicker and strongly pitted, especially in the summer wood ; the lateral walls with small, elliptical, bordered pit.s, with an oblong orifice, 2-4 per tracheid, abruptly reduced to i in the summer wood. Bordered pits lar^e, elliptical, or round, in i row. Fits on the tangential walls of the summer wood not very numerous, small, chiefl> 'onfined to the outer- most wall. Tangential. Rays rather numerous but low to medium, somewhat resinous. The fusiform rays chiefly low, narrow, the usually small resin canal with thick-walled epithelium. Ordinal ' rays conspicuously contracted at the position of the very narrow, interspersed tracheids; the paren- chyma cells thick-walled, equal and chiefly uniform, oblong, often narrow, rarely oval. -;KS ! PICEA ,g^ •• P* pvagMM, Engeltn. Blut SfriKt. CcJoraJi) Sfruet Trtuuvtrst. Growth x\na% broad TK«. varv >i.i„ ■ < . . Kui.hable summer w'lod SuaHy pS.r .„. "'.h°'''", ^"'"'^ !""""• .racheid. very unc.ual -Tof.e^ Vu^'"c^4^ ^iV^^^'* ,7"«' • .«^^^ structure U very open throuKhout. Re.in pajwaires rather fc* . J^ii and Mattering, with .mall and very une.|ual.1hick.wXd InT.hT ' cell.; thylow;* few or wanting MedullJrv r.!. L.i eP'. Pennsylvania, central Michigan, Wiscon- sin, and Minnesota, and alo...; the Allegheny Mountains to the high peaks of North Carolina (Sargent). Pleistocene deposits at Hamilton (Erie clays), Ontario ; the Moose River, Ontario ; Don Valley and the Leda Clays, Montreal. This plant occurs in considerable abundance and is essentially typical of the Oon periwl, where it is associated with another unde.scribcd :«pecies, possibly the samt. Material preserved in a natural state, though usually much altered by decay. 10. P. sitchensiB, Carr. Tidttand Spruct. Sitka S/ net Transverse. Growth rings thickish. Summer wood very prominent, equ.il to or exceeding the spring wood from which the transition is gradual, not very dense. Spring tracheids commonly strongly rounded-hexagonal, PINUS 25 thf walU rather thin, bat the Htrurn.r.. ,. , 1. i puMKe. few. not viry UruV w^^h" Ll^ '"''l* ""' ^'"y "P*" «"'" thick-walled cell,. re.iUf Medtl arl r^vVn ..' 'P'*'""""' "' ■""»"• Inent or broad, 1 cell wide diHUn7I^ ""i '""'""•'"''•P'"'"- rarely 11. °'' '"'"*"' '"9 row. 0/ tracheidn, more AWm/. Rays somewhat resinous locallv • tk. „„ . u .. marginal, rarely interspersed Snch'vm! /iT tracheids prominent, at the ends, equal to 6-^0 sbrin„ .« k ^J^' *"■*"" »«"'e*hat contracted pitted; the upj^r and lowe w^aK^:^'' = '^ the resinous ceHs and summer wo~j T ""^ "'.'.*"' ^'"^ *""'«. or in lateral wails with rathcrTew and smaS■;nr;:!^"'r'''; "".^ »""'♦» ' «»"= lenticular orifice. 1-3. more* arelvTr-^'r^T^'^' ^'""^''"^'^ Pi"» with a reduced to 2, and finalWto , SrfirH "''^"'' '" "" '"""'"" *ood .he orifice la^Kc and rouU or SuTar i n?h " ' '"*' ""P""'' '"«« = n« row and parallel with the tracS aiiT PU.ZT T "'' ''^■?'"'"« oirmrtrheTiaSr •"'"• -- Sy^ rhXsrd't^t cells. Ordinary rays rathe "b^ld rnl '"'' 'hifk^aHed epithelium position of .he\arU and S;„X''i'„'r"''^' T"'"'^'*'* '»' 'f"*^ parenchyma cells equal but vSlefr„2; '"'"';P«^'''d tracheids; the cijudi out variable from round to oval or oblong Wood llgM. .of,, „„, ^,, .1^ .^ .„,^„ ^.^^ ^^^^^ ^^^^^^ Relat' /e specific gravity Percentage tf ash residue Approximate relative fuel value fjmm JrL°^ '''""''"'' '" kilograms on miilimeters " ' U t ma e transverse strength in kilograms Ultimate resistance to loniri'udimi /-I...!,!- • 1 •. " " Resistance to longitudin.^'crush?*., ?. ?^'"« '" .•" K'^a'^" 5653 (Sarg..nt) crushing to 1.27 mm. in kilograms 1 160 0.4287 0.17 42.80 990. 77. 5653. Cliiefiy confined • . the coast nf n,:.: 1. .- i ■ . cnendin, more than 50 mil.s inland from the coa.s. (tr^ "' 17. • PINUS, 1 '<)1:k.\. Trans-. :rse. Growth rings usually broad Th,. m«, 1 summer wood variable Res n n,. -. '^ "' '"'" Prominent prominent thyloses and tHn writ^rv^r^Tr "'^^"•' '^^f^' '"«^' ""'^ ^. lium. Resinlcells wholly wani^ni'''' '"""'^'•^' '^'^^eral-layered epithe- .racheid so as to for^T^ri ^ !t ^^Hi^S^S. ^l^^iti: 292 ANATOMY OF THE GYMNOSPERMS of one or two kinds. Bordered pits on the tangential walls of the sum- mer wood either numerous (Sec. I) or usually wanting (Sec. II). Tracheids wholly without spirals. Resinous tracheids sometimes pres- ent, the resin forming radial plates opposite the rays and simulating Sanio's bands. ToHgential. Fusiform rays chiefly large and broad ; the cells of the inflated portion chiefly large and thin-walled: the central tract occupied by I large resin passage with thyloses and thin-walled epithelium. Ordi- nary rays chiefly I -seriate, more or less conspicuously contracted by the interspersed tracheids. 11 Synopsis of Species A. PINUS PROPER Existing Species Sec. I. Pits on the tangential walls of the summer wood prom- inent. Medullary tracheids prominent, sparingly interspersed, their upper and lower walls not dentate. A. The lateral walls of the ray cells (radial) with small, numer- ous, and more or less conspicuously bordered pits ; the upper and lower walls thick and coarsely pitted ; the terminal walls coarsely pitted ; the thick side walls (tangential) not inflated or incurved. The rays sometimes show thin-walled cells with- out pits, which are conterminous and interspersed. Ray cells (radial) of I kind only, all thick-walled and strongly pitted. Rays nonresinous (radial), the tracheids numerous, marginal, often interspersed. Pits on the lateral walls of the ray cells 1-4, chiefly 4, throughout, but finally 2, per tracheid in the outer summer wood. Ray cell.s (tangential) conspicuously unequal and variable, from round to oval or oblong, those of the low rays often three times higher than wide. 3. P. monophylla. Rays more or less resinous (radial), the tracheids marginal, sparingly or rarely interspersed. Pits on the lateral walls of the ray cells 2»-4 per tracheid throughout. Ordinary rays (tangential) sparingly resinous, somewhat con- tracted by occasionally inter.sper.sed, narrowly oval, or oblong tracheids ; the cells equal and chiefly uniform, oval to obiong, rarely narrow. I. P. Parryana. Ordinary rays (tangential) somewhat resinous, rather broad, not perceptibly contracted by the occasionally interspersed PINUS 293 and equal tracheids ; the cells very equal, chiefly verv uniform, narrowly oval or oblonK. rarely broader 2. 1'. cembroides. Pits on the lateral walls of the ray cells ,-5 throughout, or finally 1-2, per tracheid m the summer wood. Ordinary rays rather broad and nonresinous (tangential), somewhat contracted by the narrower and smaller, occasion- ally interspersed tracheids ; the cells very equal and uniform, narrowly oval to oblong. 4- P. Balfouriana. Ray cells (radial) of 2 kinds: (,) thick-walled and strongly pitted- (2) th.n-walled, devoid of pits, conterminous, and interspersed P.ts on the lateral walls of the ray cells 3-6, soon 4, or in the outer summer wood 2, per tracheid. Ordinary rays (tangential) nonresinous, numerous, the cells equal uniform, oval, or oblong. ^ Fusiform rays (tangential) few, narrow. 5- P- aristata. Pits on the lateral walls of the ray cells ,-4 throughout, or in the marginal cells upwards of 5 or 6, per tracheid. Ordinary rays (tangential) numerous, broad, the cells chiefly equal uniform, oval, and narrow. ' ' Fusiform rays (tangential) rather numerous, small, and narrow 6. P. edulis. B. Lateral walls of the ray cells (radial) with large, open, and simple, oval, or lenticular pits, 1-2 per tracheid; the upper and lower walls thin and distantly or even obscurely pitted- the terminal walls thin and entire or locally thickened ; the' thin .side walls (tangential) either inflated or incurved Ray cells (transverse or tangential) with their very thin side walls strongly inflated and projecting into the cavities of the adjacent tracheids Pits on the lateral walls of the ray cells oval or .sc|uarisb, or finally lenticular, 1-2, chiefly i, per tracheid throughout. Resin passages numerous and large, chiefly in or near the summer wood ; when in the former situation, central to a large tract of thin-walled tracheids. 10. P. reflexa. Ray cells (transverse or tangential) with their thin side walls not strongly inflated, but commonly incurved or sometimes convex. Pits on the lateral walls of the ray cells chiefly 1-2 per tracheid. Resinous tracheids (radial) not present. Rays (tangential) strongly resinous, the cells oval, unequal, variable. 294 ANATOMY OF THE GYMNOSPERMS 5 i^' Pits on the lateral walls of the ray cells 1-2, in the sum mer wood reduced to I, per tracheid. 8. F. monticola. Rays (tangential) nonresinous. Ray cells (tangential) oval, equal, and uniform. Pits on the lateral walls of the ray cells 1-2, or in the marginal cells 3-4, per tracheid. 9. P. flexilis. Ray cells (tangential), oblong, narrow, equal,and uniform. Pits on the lateral walls of the ray cells 1-2 through- out, rarely 3, per tracheid. 11. • P. strobus. Ray cells (tangential) chiefly equal, but more or less vari- able, from broadly to narrowly oval or oblong. Pits on the lateral walls of the ray cells 2 per tra- cheid throughout, rarely i or 3. 7. P. I ambertiana. Ray cells (tangential; oblong and narrow, more rarely oval and broader, not very variable. Pits on the lateral walls of the ray cells i per tra- cheid throughout, or in the early spring wood 2 per tracheid. 12. P. parviflora. Resinous tracheids (radial or tangential) present, the resin in plates opposite the rays and simulating Sanio's bands. Rays (tangential) nonresinous. Ray cells (tangential) oval or oblong, not very variable. Pits on the lateral walls of the ray cells i per tra- cheid throughout, more rarely 2. 13. P. albicaulis. Ray cells (tangential) oblong and narrow, more rarely oval and broader, not very variable. Pits on the lateral walls of the ray cells 1 ptr tracheid throughout, or in the early spring wood 2 per tracheid. 12. P. parviflora. ^SVf . //. Pi/s on the tangential walls of the summer wood usu- ally wanting. Medullary tracheids prominent, more or less, often strongly, interspersed, their tipper and lower walls den- tate or the teeth so prolonged and united across the cavity as to form a more or less definite and sometimes very strongly defined reticulum. I'lNUS 295 chiefly I, and not exceeding 2, per tracheid. Ray cells of 1 kind only. Epithelium of the resin passages resinous. Bordered pits in i row, sometimes in pairs Ray tracheids simply dentate, rarely interspersed Pits on the lateral walls of the ray cells .-2, 'chiefly I, per tracheid. ' 21. P. resinosa. Ray tracheids simply dentate, but numerous and inter- spersed and often predominant. Pits on the lateral walls of the ray ceils large, oval, oblong, or lenticular. ,-2, chiefly ,, per tracheid. 22. P. tropicalis. Pits on the lateral walls of the rav ppIIc u,„ j dered in the summer wH ' '"^' '"' conspicuously bor- Epithelium of the resin pas.sages nonre.sinous Resin passages (transverse) large, numerous, scattering. Bordered pits in i row. Ray tracheids (radial or tangential) simply dentate not interspersed. Pits on the lateral wall.s of the ray cells i rarely 2, per tracheid. 23. P. Thunbergii. Ray tracheids (radial or tangential) somewhat inter- spersed, sparingly reticulated in the summer wood Pits on the lateral walls of the ray cells strictly I per tracheid. 24. P. densiflora. ^man r„d'' ''*T' ?"' ""' '•'^ ">• «"^ 8-"=*% rather Jr^cheid "^ ' *"' "''*'''''• ^' '"'^' ^ °' '"°'« P" Kay cells (radial) of i kind only and thin-walled Fusiform rays (. ngential) with the cells of the inflated .nion aUor chiefly rather thick-walled. ^nona^/or """restor °' "' """ '''"'" (transverse) chiefly in ,-2 rows. Summer wood dense. Bordered pits in i row, or sometimes in pairs. Pits on the lateral walls of the lay cells 1-6 per tra- cheid. ■iir.>wwfc.a ,f ■ 2Q6 ANATOMY OF THE GYMNOSPERMS s Ray tracheids strongly predominant and strongly reticulated throughout. 17. P. Banksiana. Fusiform r::iys (tangential) with the cells of the inflated portion a/i or chiefly thin-walled, all broken out. Epithelium of the resin passages (transverse) chiefly or wholly in I row, nonresinous (rarely resinous in P. txda and P. rigida). Summer wood open. Bordered pits in i row, sometimes in pairs. Pits on the lateral walls of the ray cells 1-5, chiefly 2, per tracheid, becoming bordered in the summer wood. Ray tracheids sparingly inters] lersed, strongly reticulated throughout. 15. P. rigida. Pits on the lateral walls of the ray cells 1-4, rarely ;, per tracheid. Ray tracheids more or less reticulated in the summer wood, often interspersed. 25. P. Murrayana. Bordered pits in 1-2 rows. Pits on the lateral walls of the ray cells 1-6, chiefly 2-4, per tracheid. Ray tracheids sparingly (very rarely strongly) reticulated throughout. 39. P. taeda, Linn. Pits on the lateral walls of the ray cells i -5 per tracheid. Ray tracheids when interspersed very low, strongly reticulated throughout. 14. P. clausa. Summer wood dense. Bordered pits in 1-2 rows. Pits on the lateral walls of the ray cells 1-6, chiefly 2-4, per tracheid. Ray tracheids sparingly (rarely strongly) retic- ulated throughout. 39. P. taeda. Ray tracheids high, very strongly reticulated throughout. The ray cells apparently all of i kind, but differentiating slightly. 41. P. cubensis. PINUS 297 Pits on the lateral walls of the ray cells 1-5 per tra- cheid. Ray tracheids strongly reticulated throughout, often predominant, and, when interspersed, very low. IJ. J . clausa. Pits on th.' lateral walls of the ray cells 1-4 per ira- '.heid. Hay tracheids chiefly high, conspici ously pre- dominant, and strongly reticulatec hroughout. 20. P. echinata. Bordered pits in 1 row, sometimes in pairs. Pits on the lateral walls of the ray cells 1-4 per tracheid. Ray tracheids chiefly high, conspicuously pre- dominant.and strongly reticulated throughout. 20. P. echinata. Epithelium of the resin passages (transverse) distinctly in 1 or more rows, nonresinous. Summer wood dense, rarely somewhat open. Bordered pits in 1-2 rows. Pits on the lateral walls of the ray cells 1-6, chiefly 2-4, per tracneid. Ray tracheids sparingly (rarely strongly) reti- • ulated throughout. 39. P. tasda. Ray tracheids high, very strongly reticulated throughout. Ray cells apparently all of i kind, but differentiating slightly. 4'- P. cubensis. Pits on the lateral walls of the ray cells 2-5, chiefly 4i per tracheid. Ray tracheids commonly predominant and inter- spersed, very strongly reticulated throughout. 40. P. palustris. Epithelium of the resin passages (transverse) distinctly in i or more rows, resi.. as. Summer wood open. Bordered pits in 1 row or sometimes in pairs. Pits on the lateral walls of the ray cells 1-4, rarely 5, per tracheid. 29^ ANATOMY OF THE GYMNOSPERMS Ray trachekls sparingly interspersed, strongly reticulated throughout. 16. I', serotina. Pits on the lateral walls of the ray cells 1-5, chiefly 2, per tracheid, becoming bordered in the summer wood. R->y tracheids sparingly interspersed, strongly reticulated throughout. 15. P. rigida. Bordered pits in 1 row. Pits on the lateral walls of the ray cells 1-6, chiefly 2 or 3, per tracheid, but very variable. Ray tracheids often predominant, interspersed, sparingly leticulated. 19. P. glabra. Summer wood dense (sometimes open in P. txda and F. cubensis). Bordered pits in 1-2 rows. Pits on the lateral walls of the ray cells 1-6, chiefly 2-4, per tracheid. Ray tracheids sparingly (very rarely strongly) reticulated throughout. 39. P. ta;da. Ray tracheids high, very strongly reticulated throughout. Ray cells apparently all of one kind, hut differentiating slightly. 41. P. cubensis. Pits on the lateral walls of the ray cells 2-5, chiefly 4, per tracheid. Ray tracheids commonly predominant and inter- spersed, very strongly reticulated throughout. 40. P. palustris. Bordered pits in 1 row. Pits on the lateral walls of the ray cells 1-6, chiefly 2 or 3, per tracheid, but very variable. Ray tracheids interspersed, often predominant, sparingly reticulated. 19. P. glabra. Bordered pits in i row, or sometimes in pairs. Pits on the lateral walls of the ray cells 1-6, chiefly 2-4, per tracheid. PINUS 299 i Ray cells apparently all of one kind, but differentiating slightly. 41. F cubensis. »7. P. Banksiana. Pitson the lateral walls of the ray cells ,-4. rarely , per tracheid. ^ " 5' Ray tracheids sparingly interspersed, strongly reticulated throughout. ^ * 16. P. serotina. Pits on the lateral walls of the ray cells ,-5, chiefly ^.^J tracheid. becoming bordered in J™!' Ray tracheids sparingly interspersed, strongly reticulated throughout. ^^ '5. P. rigida. D,. II ^ J. . '^- ^- contorta. chiefly thick-walled '"''^'*'* P°^'*°n "^'or Summer wood dense. Bordered pits in , row or sometimes in pairs Pits on the lateral walls of the ray cells (.) .-3 bordered ,„ the summer wood ; and r-) .-4 cHeflv 2-3. per tracheid. ^ ^' ^ Ray tracheids more or less interspersed, retic- ulated throughout. P . . ,. 34. P. pungens. Summer wood open. i>' ,vj •.,» .n 300 ANATOMY OF THE GYMNOSPERMS Bordered pits in i row or sometimes in pain. Pits on the lateral walls of the ray cells i-j, chiefly 2, per tracheid, l)ecoming bordered in the summer wood. Kay tracheids sparingly interspersed, strongly reticulated throughout. 15. P. rigida. Pits on the lateral walls of the ray cells (i) 1-4; and (2) 1-3, chiefly 2, per tracheid, the two forms of cells clearly defined. Kay tracheids reticulated in the summer wood, predominant in the low rays of which they often compose the entire structure. 36. P. muricata. Pits on the lateral walls of the ray cells 2-4 through- out, the two forms of cells merging and not always clearly defined. Kay tracheids strongly dentate and becoming sparingly reticulated in the summer wood, interspersed, often predominant. 30. P. chihuahuana. Summer wood dense. Bordered pits in I row or sometimes in pairs. Pits on the lateral walls of the ray cells 2-4 through- out, the two forms of cells merging and not always clearly differentiated. Kay tracheids strongly dentate and becoming sparingly reticulated in the summer wood, interspersed, often predominant. 30. P. chihuahuana. Fusiform rays (tangential) with the cells of the inflated portion all thin-walled and usually broken out. Epithelium of the resin passages (transverse) in 1-2 or more rows, nonresinous. Summer wood open. Bordered pits in I row. Pits on the lateral walls of the ray cells 1-6, chicHy 2 or 3, per tracheid, but very variable. Kay tracheids interspersed, often predominant, sparingly reticulated. 19. P. glabra. Pits on the lateral walls of the ray cells (i) 1-4 ; and (2) 2-4, chiefly 4, per tracheid. PINUS 301 Ray trachelds predominant, sparingly retic- ulated. 33- P- scopuk um. Bordered pits in 1 row, sometime!! in pairs. Pits on the lateral walls of the ray cells 1-4, rarely 5 per tracheid. Ray iracheids more or less reticulated in the summer wood, often interspersed. 25- P. Murrayana. Pits on the lateral walls of the ray cells 2-5, chiefly 3-4. per tracheid. Ray tracheids strongly predominant, strongly dentate, and more or less reticulated through- out. 31- P. Jeflreyi. Pits on the lateral walls of the ray cells (i) 1-4. and (2) >-3. chiefly 2, per tracheid. Ray tracheids often predominant, reticulated throughout. 27. P. Coulteri. Bordered pits in 1-2 rows. Pits on the lateral walls of the ray cells 1-6, chiefly 2-4, per tracheid. Ray tracheids sparingly (rarely strongly) retic- ulated throughout. 39- P. ticda. Ray tracheids high, very strongly reticulated throughout. 41. P. cubensis. Summer wood dense, more rarely somewhat open. Bordered pits in 1 row. Pits on the lateral walls of the ray cells (1) 1-4; and (2) 2-4, chiefly 4, per tracheid. Ray tracheids predominant, sparinglyreticulated. 33- P. scopulorum. Bordered pits in I row, .sometimes in pairs. Pits on the lateral walls of the ray cells (1)1-4 ; and (2) 1-3, chiefly 2, per tracheid, the two forms of cells clearly defined. Ray tracheids reticulated in the summer wood, predominant in the low rays of which they often compose the entire structure. 36. P. muricata. *; 3oa ANATOMY OF THE GYMNOSPERMS PiU on the lateral walk of the ray cell* (i) 1-3, bordered in the •ummcr wood; and (3) 1-4, chiefly 3-3, per tracheid. Ray tracheids more or leaa Intenpened, retic- ulated throughout. 34. P. pungent. Bordered pits in 1-3 rows. Pita on the lateral walls of the ray cells 3-5, chiefly 4, per tracheid. Ray tracheids commonly '-^minant and inter- spersed, very strongly 1 e .11. ated throughou t . 40. P. palustris. Pits on the latei il walls of the ray cells 1-6, chiefly 3-4, per tracheid. Ray tracheids high, very strongly reticulated throughout. 41. P. cuu<:nsis. Epithelium of the resin passage-^ (transverse) in i-3 or more ro'vs, resinous. Summer wood dense. Bordered pits in i row. Pits on the lateral walls of the ray cells 1-6, chiefly 3 or 3, per tracheid, but very variable. Ray tracheids interspersed, often predominant, sparingly reticulated. 19. P. glabra. Pits on the lateral walls of the ray cells 2-4 (kt tracheid, rarely 5. Kay tracheids strongly reticulated, often pre- dominant. 32. P. ponderosa. Bordered pits in i row, sometimes in pairs. Pits on the lateral walls of the ray cells 1-6, chicriy 2-4, per tracheid. Ray tracheids sparingly (rarely strongly) retic- ulated thr')ughout. 39. P. taeda. Pits on the lateral wMls of the ray cells (i) 2-6, rhlefl • 4 ; and (2) 1-4, chiefly 4, per tracheid. Ray tracheids predominant, very strongly ri'tic- ulated throughout. 35. P. inops. I'lNlS 303 Bordered pits in 1-2 rows. Pits on the lateral wall* of the ray itlln 1-^,, chiefly 2-4, per trachcid. Ray tracheidH hi^h, very iitronj{ly reticulated throughout. 41- •'. cubensis. Pits on the lateral walls of the ray cells 2-5, chiefly 4) l)cr tracheid. Kay trachcids sparingly interspersed, predomi- nant, strongly dentate, and .somewhat retic- ulated in the summer wood. 38. I'. Sabiniana. Ray tracheids commonly predominant, often interspersed and very strongly reticulated throughout. 40. F. palastris. Pits on the lateral walls of the ray cells 1-6, thitfly 4i |>er tracheid. Ray tracheids sparingly (rarely strongly) retic- ulated throu-'hout. 39. P. taida. Summer wood open. Bordered pits in 1 row or .sometimes in pairs, the latter sometimes numerous (P. arizonica). Pita on the lateral walls of the ray cells (1) i-j, rarely 6, chiefly 2 ; and (2) 1-3 per tracheid. Tracheids sparingly predominant and sparingly reticulated. 37- P. insignis. Pits on the lateral walls of the ray cells (1)2-4; and (2) 2-3 per tracheid. Ray trachcids strongly predominant and strongly reticulated. 29. P. Torreyana. Pits on the lateral walls of the ray cell.s 2-4 per tracheid. Kay tracheids dentate and .somewhat reticulated throughout, sometimes interspersed and pre- dominant. 28. I*. tul)erculata. Pits on the lateral walls of the ray cills 2-4, chietiy 4. per tracheid. 304 ANAIX)MY OF THE (lYMNOSPERMS Ray trachcidn itironKly predominant, utronKly dentate, and tomcwhat reticulated In the Mummcr wood. 26. v. arixonica. PitH on the lateral witllK of the ray cells (1) i-(>, chiefly 4 ; and (2) 1-4, chiefly 4, per tracheid. Kay tracheidH predominant, very strongly retit ulated throughout. 35. v. inops. Bordered pits In 1 row. PitH on the lateral walU of the ray cells 1-6, chiefly 2 or 3, per tracheid, but very variable. Kay tracheids often predominant, interspersed, sparingly reticulated. 19. P. glabra. B. ••PITYOXYLON (Pinoxylon) F.xlinct Species Kay tracheids present. Upper and lower wall.s of the ray tracheids dentate. Bordered pits in 2 rows. Kesin passages numerou.s, large, scattering. • Pits on the lateral walls of the ray cells 1-2 per tracheid. 42. •• 1'. (Pinoxylon) dacotense. Upper and lower walls of the ray tracheids not dentate. Bordered pits in i row. Transition from the spring to the summer wood gradual. Or(iii..-iry rays (tanijential) 1-2 .seriate in part. Kcsin passages (tran.sverse) very large. Medullary rays (transverse) distant 3-8, more rarely 8, rows of tracheids. 43. •• P. Aldersopi. Ordinary rays (tangential) strictly 1 -seriate. Kesin passages (transverse) very large. Medullary rays (traasverse) distant upwards of 25 rows of tracheids. 44. * • P. amethy.stinum. Resin passages (transverse) r.ither large, the r|ii- thflial cells resinous. Medullary rays (transverse) distant upwanU uf 9, or rarely 1 5, rows of tracheids. 45. ••P. (Pinus) Columbiana. IMNUS 305 Rc»ln p»»imgt» obliterated. Bordered pim on the lateral wall* of the ray celU a-3 per trachcid. 4fi •• I'. J'eaii. Bordered pit. in 1-3. chiefly 2, row.,, round or hexagonal. Ordinary rays (tsnKenfial) 2-iieriate in part. Renin pansageii not rcprewnted. Kay tracheid* wholly wanting. ^^' ' * '" ''''•^"•*- Bordered pits in 1 row. Resin pas»aKe» numerous, large, chiefly in the summer wood. filled with prominent and resinou. thylose.. the epiihelium 1-2 celb thick, not extended into parenchymatous tracts. 4H. • • I', .statcnen.se. Resin passages numerous, small, chiefly in the summer wood, devoid of thylo.sPs, the epithelium composed of a single layer which ex- tendsintoaprominentandoften broad tract of wood parenchyma. 49- ••P. scituatensc. A. PINUS PROPER Existing Species Section /. Soft Pines 1. P. Parryaiu, Engclm. Pineit. Nut Pine Transverse. Growth rings chiefly narrow but very variable Summer u,~^ very open and chiefl> ver/thin, but in the Cader Hnrujwa^ of one half the spring wood, from which the transition is ven gradual the trache,ds in regular rows, con.spicuou.sly unequal Tnd founded Spring trachedssquarish-hexagonal, unequal in regular rows the vJlfs rather thin. Medullary rays numerou.s, broad, 1 cell wide d stan, , a rows of trachelds. Resin pas-sages numerous, med urn and variable very scattering throughout the entire growth ring; the ;es eral fa ered epithelium composed of very large, rather thick^^alled cells Ze or Radial. Rays sparingly resinoas; the tracheids numerou.s, marginal, hith a'oVtu^TnTht- P='--'^>"'=^ ->• ""^ ^•'''=">- "t^iKHt^nd VS \T.^1- u narrower growth rings and in the summer wood thick and conspicuously though often distantly pitted, becoming more strongly pi„ed in the fusiform cells; the terminal walls localK ,h ck ened or co. ely pitted ; the lateral walls with small, round pits w th a more or less definite though variable border and a lenticular orifice —4 per tracheid. Bordered pits in 1 row, rather numerou.s, broadly ii BiJ 306 ANATOMV OF I'HE (IVMNOSPKRMS elliptical. Pits on the tangential walls of the summer wood rather numerous, small and chiefly confined to the two outermost walls. Resin- ous tracheids wanting. Tangential. Fusiform rays numerous, very narrow ; the cells of the inflated portion all thin-walled and usually much broken out ; the .somewli.it thicker-walled structure of the central tract generally present and embracing a small resin canal. Ordinary rays sparingly resinous, medium, numerous, broad, somewhat contracted by occasionallv ,',cr. -spersed, narrowly oval or oblong tracheids; the thick-w l?j,l c.ilv usually equal and .somewhat uniform, oval to oblong, rap y narrow. Resinous tracheids wanting. A small tree 6-9 m. high, with a trunk upwards of .45 m. in diai 'c- VVood light, soft, close grained, and compact. Relative specific gravity 0.5675 Percentage of ash residue 0.54 Approximate relative fuel value 56.44 Coefficient of elasticity in kilograms on millimeters . . 378. Ultimate transverse strength in kilograms 182. Ultimate resistance to cru.shing in kilograms .... 5420. Resistance to indentation to 1.27 mm. in kilograms . . 3126. (Sargent) Larkin's Station, San Diego County, California, and southward info Lower California, where it forms extensive forests on high mesas and slopes (Sargent). 2. P. cembroides, Zucc. Piiion. Xiit Pine Traiisi'crse. Growth rings not broad, variable, more or less conspicuously double, the structure as a whole rather den.se. Summer wood rather open, either very thin or upwards of equal to the spring wood, from which the transition is very gradual and from which it cannot he readily distinguished; the tracliiids distinctly rounded, unequal, but in rather regular rows. Spring tracheids hexagonal, not large, very un- equal and variable, but in regular rows. Medullai v rays prominent and numerous, broad, i cell wide, distant i-6, rarely 10', rows of tra- cheids. Resin passages numerous, not large, chiefly in the middle or inner portion of the growth ring, the several-layered epithelium com- posed of large, thick- and thin-walled, nonresinous cells. Radial. Rays somewhat resinous, the resin localized, granular, rarely mas- sive ; the tracheids not very numerous, marginal, rarely interspersed ; the lateral walls with very small pits about 2 per tra'cheid. Paitii- chyma ray cells conspicuously contracted at the ends throughoul, .short, equal to 8-10 tracheids; the upper and lower walls thick, iini form, conspicuou.sly pitted throughout ; the terminal walls thin bnl locally thickened or more often coarsely pitted ; the lateral walls \\\\\\ small, round pits, with a more or less obvious though very une(|u.il border and a lenticular orifice, at first 2-4, but in the summer woi'd PINUS 307 ^^'Ttll ^'3.'Vo K2^!:^i^' ""tTT'- ''■' '" ' numerous. Pits on the tanc^nt^l vvalU nf !l"^ '"'"' '" ' '■°«' and numerous, extending yfrinfn 1 *^^ '""1"'" "■°"'' ^"'^» cheids wanting ""'""'*'"« '^"^ '"'" ">« summer wood. Ke.sinous tra- the persistent, thicker Vali^d'tn^ra ,'a ^ wtch^in^duH"^' ""^! broLel-. Res;2s\7c:elTa'nu"nl""""'^°^^'°'-°'^'°"^' --'^ A small tree 6-7 m. high, with a trunk rarely exceeding .30 Wood light, soft, very close grained, and compact. m. in diameter. Specific gravity Percentage of ash residue °*^5i2 (Sargent) °-9° Dry ridges and slopes at 3500 feet el Arizona and through northern Mexico (Sargent). evation. Santa Catalina Mountains of a] fIS 1 3. p. monophylla, Torr. Pittflit. A'ut Pine A<7>fm/. Rays non res, nous ; the tracheids numerou.s, mar-inal often int.r ZTJ- ■ '^r'^^^y^'' '"''- ""■^^'^°^'' «'™"«'y con racLd a, the end' the terminal walls commonly thick and coarselv nit.^ri hi J ower walls thick and strongly pitter,h?h eral Sk w'th''''" '"'^ ess obviously-border^d pits^ 'wfth a prlngJd s i, liie orifice whic°h cheTfn ir'^t^ !r "^ '''''" 'P''^^ "--' --rchiefl; 4 per .a che^d, final y reduced to 2 in the outer summer wood. Bordered ns numerous, ,n , row, dliptical. Pits on the tangential waifs of the sum rousTr^^h-eidTrtinT'""'" '" '-''' -"-^''''--^ '-«'-!- 'Z- ^""■fn'JZ^A ^'"■1-^°''",' '■"^'' ""'" """-erous and narrow, the cells of the nrtated portion large and very thin-walled, often much broken ou he pemsten, central tract containing a resin canal of n,edium s ze Ord SSL"d 'trrh^d'^fh • ''"W' ■'"^"^'"«'>' ^'^'^'"°"^' - contacted '; interspersed trache.ds ; the cells conspicuou.sly unequal and variable! _hsM -i e 308 ANATOMY OF THE GYMNOSPERMS from round to oval or oblong, those of the low rays often three times higher than wide, those of the higher rays sometimes twice the width of others. A small, bushy tree 4-6 m. high, with a trunk upwards of i m. in diameter. Wood light, soft, weak, brittle, close grained, and compact. Specific gravity 0.5658 Percentage of ash residue 0.68 Approximate relative fuel value 56.20 Coefficient of elasticity in kilograms on millimeters . . 435. Ultimate transverse strength in kilograms 123. Ultimate resistance to longitudinal crushing in kilograms 4389. Resistance to indentation to 1.27 mm. in kilograms . . 2713. (Sargent) Dry gravelly slopes and mesas between 3000 and 6000 feet elevation. Near Lake Utah, to the eastern foothills of the California Sierras, and south along the mountain ranges of the Great Basin to the San Francisco Mountains of eastern Arizona (Sargent). 4. P. Balfouriana, A. Murr. Foxtail Pine Trans'jerse. Growth rings narrow, uniform, the structure very open through- out. Summer wood thin, of 2-6 tracheids and open, the tracheids large in regular rows, uniform, the transition from the spring wood gradual. Spring tracheids rather large, very thin-walled, hexagonal, chiefly in regular rows, but conspicuously unequal. Medullary rays rather prominent and numerous, broad, i cell wide, distant 2-8 rows of tracheids. Resin passages medium, rather numerous, widp'y scatter- ing, the somewhat extensive epithelium composed of 1." n-walled, more or less resinous cells. Radial. Rays sparingly resinous ; the tracheids rather numt. . rginal, rarely interspersed. Parenchyma ray cells short and sirai^ i ; the upper and lower walls thick and very strongly pitted ; the lateral walls with numerous, small, round, or oval pits, at first with a prominent bordtr and narrowly lenticular, prolonged orifice, the border becoming obscure and variable toward the summer wood, and the orifice broader, 1-5 per tracheid, finally reduced to 1-2 in the summer wood. Bordered pits numerous and round, in 1 row, nearly as broad as the tracheid. Pits on the tangential walls of the summer wood very numerous and contig- uous on the outermost wall, becoming scattering in the older tracheids, small but rather broadly lenticular. Resinous tracheids wanting. Tangential. Fusiform rays narrow, the cells of the inflated portion larijc, thin-walled, resinous, the resi- ^.assage not large. Ordinary rays medium to high, rather broad, ■ onresinou.s, and somewhat contracted by the rather narrower, smaller, and occasionally interspersed tra cheids ; the thick-walled cells very equal and uniform, narrowly oval to oblong. PINUS 30^ A small tree 15-19 m. hiKh, with a trunk upwards of .90 m. in diameter Wood I.Kht, soft, weak, brittle, very close Rrained, compact, satiny, and susceptible of a good polish. Specific gravity Percentage of ash residue . . . . " o'lV^ Approximate relative fuel value . . , . 1 7 Coefficient of elasticity in kilograms on millimeters ■ ' ciu Ultimate transverse strength in kilograms ,«, Ultimate resistance to longitudinal crushing in kilograms ^qs' Resistance to indentation to 1 .27 mm. in kilogrpms 2^50' (Sargent) ^^ Dry, open ridges, forming upon Scott's Mountain a broad belt of open forest between 5000 and 8000 feet elevation. Mt. Whitney, California and about the head waters of the King and Kern rivers (Sargent) 5. P. aristata, Engelm. Foxtail Pine. Hickory Pine Transverse. Summer wood thin, upwards of 8 tracheids, barely distinguish- able, very open, the tracheids often variable in more or less conspic- uously irregular rows. Spring tracheids rather large, conspicuously squari-sh-hexagonal, very uniform in regular rows, the walls thin the transition to the summer wood very gradual. Medullary rays rather KL' k'^ •'''■""''■ ' "" ^'^'^ '"^*^"* ^-*' -""^-^ r-^^'y .o^ows of tracheids. Resm pa.ssages numerous, rather large, the rather exten- non're'sinousTeJr"'' '''''''""'" ^°'"P°^^'^ ^' '^'«^^' ^'^ *^--^"^d. Radial. Rays sparingly resinous throughout; the tracheids numerous, mar- ginal, sparing y interspersed. Parenchyma ray cells of 2 kinds • ( ) the cells more or less strongly contracted at the ends ; the upper and lower walls thick, strongly pitted; the terminal walls coarsely pitted " the lateral walls with round or oval but rather small pits, with T lenticular orifice and an obvious border which becomes variable and obscure toward the summer wood, at first 3-6, soon uniformly about 4, or in hL^s^h'' ^TfJ ""'"^ '• P"" '''"'^^''^ ! ■■»"d <2) "">* occasionally nterspersed and oftt.; conterminous with the cells of the first kind; the terminal walls thin and not pitted, but often locally thickened the upper and lower walls thin and not pitted ; the lateral walls devoid VJT.A ^%T P'^^ numerous, in i row, elliptical, as broad as the tracheid. Pits on the tangential walls of the summer wood chiefly confined to the outermost wall, where they are numerous, apparently not extending beyond the second wall, small, distinctly lenticular. Resinous tracheids wanting. ^ Tangential Y^^Morm rays rather few, narrow, the cells of the .short termi- nals thick-walled, tho.se of the inflated portion very thin-walled and much broken down or wanting, the more persistent central tract with a rather small resin passage with delicate epithelium. Ordinary rays |!'. 310 ANATOMY OF THE GYMNOSPERMS numerous, nonrcsinous, low to med'um, slightly contracted by the occasionally interspersed tracheids. Parenchyma ray cells not very thick-walled, equal, rather uniform and oval, more rarely becoming either round, oval, or oblong; sometimes with interspersed thin-walled cells of similar form and size. A tree 15-30 m. high, with a trunk upwards of 2.40 m. in diameter. Wood light, soft, not strong, very close grained, and compact. Specific gravity 0557' Percentage of ash residue 0.30 Approximate relative fuel value ', ^^]^(, Coefficient of elasticity in kilograms on millimeters . . yij. Ultimate transverse strength in kilograms 279! Ultimate resistance to longitudinal crushing in kilograms 5209! Resistance to indentation to 1.27 mm. in kilograms . . 2140 (Sargent) Dry, gravelly ridges ; mountains of southeastern California, Nevada, north- ern Arizona, and southern Utah to Colorado above 7500 feet, in Colorado reaching 12,000 feet (Sargent). 6, P. edulis, Engelm. PiitoH. A'ut Pine Transverse. Growth rings narrow, unequal. Summer wood thin, of 3-4 tracheids, and not prominent, but very open throughout ; the tracheids strongly unequal in conspicuously irregular rows, the walls thin, the transition to the spring wood gradual. Spring tracheids open, squarish, unequal, and in more or less irregular rows, the walls thin. Medullary rays not very prominent, numerous, rather broad, 1 cell wide, dis- tant 2-7 rows of tracheids. Resin passages numerous, large, the many-layered epithelium often forming extensive tracts composed of large and very variable, often thick ailed, somewhat resinous cells. Radial. Rays very sparingly resinous ; the tracheids marginal, rarely inter spersed. Parenchyma ray cells conspicuously narrower at the ends, short, of 2 kinds: (i) the upper and lower walls thick and entire or distantly pitted, becoming more strongly pitted locally or in the sum- mer wood; the terminal walls generally thick and coarsely pitted or rarely thin and devoid of pits; the lateral walls with small and round pits with a variable, often obscure border and a lenticular orifice, 1-4, more rarely 5 or 6, in the marginal cells, in the summer wood becomini; 2, per tracheid ; and (2) thin-walled cells sparingly interspersed and conterminous with those of the first kind ; the terminal walls thin and locally thickened; the upper and lower as well as the lateral walls devro;d of pits. Bordered pits numerous, small, elliptical, in 1 row. Pits on the tangential walls of the summer tracheids numerous on the outermost wall, becoming fewer in the older tracheids, rather small and broadly lenticular. Re.sinous tracheids wanting. PINUS 3M 7a//^.w///,,/. Fusiform rays rather nun,er,,us, rhiefly small and narrow ■ tl.c inflated portion with rather large and very thiii-wallcd re U Vk^ ' • nTr^rici:!! bv^he^^^- T 'V '" ^^'^^^o^^^^, not •■ei^tncted by the equal and occasionally interspersed trachpi,k the cells ch.eriy equal, tather uniform, oval, chiefly narrow -nd thiJl' g7S; Eght"''""" ""' '"'^^^p^^'^^ ihin.waid"c:;s"oft:'„'^ii A small tree 6-9 m. high, with a trunk upward, of .90 m. in diameter. Wood hght, soft not strong, brittle, close grained, compact, and durable in contact ..ith the soil. uiauic m Specific gravity Percentage of ash lesidue . Approximate relative fuel value Coefficient of elasticity in kilograms on millimeters .' ' 0.6388 0.62 63.49 iTi.:„ . , ■' -s,.-.iia uii iiiiiiiiiiciers . . . 421 Ultimate .ran.sverse strength in kilograms . . 7„ , Ultimate resistance to longitudinal crushing in kilograms qc^S Res.st'.nce to indentation to 1.27 mm. in kilograms "^ (Sargent) 9> 78 3388. Eastern base of Pikes Peak, Colorado; south through New Mexico to the mountains of western Texas. Dry mesas and slopes, generally on lime or sandstone, reaching elevati mis of 9000 feet in Colorado (Sargent). 7. P. Lambertiana, Douglas Su^ar Pine ^'"'^ w7ht?'nn:'''.K"T.K'-'"'°^' ""'^°™- Summer wood about one tSyJ^ ^^"^ ""^ •''P""« ^°°d' ^™'" «hich the transition is gradual, the structure rather open. Spring tracheids large squarish hexagonal, in regular rows, very unifo'rm.ihe walls thir^^Xl 'ar- rays not very' prominent or numerous, rather broad, i cell wide, d"s am th". en ,r'r°^ "■''''"^'- ^"'=^ P^^^^'S^^ ^"y '"f«e, rather numemus SreS'SlTvli^Tsir:"^ '''■'-' '='>"^ ^-P-'^ °' very thD J^adial. Rays barely if at all resinous ; the tracheids short, rather broad marginal and sparingly interspersed and then very narrow Parenchyma pitU the r ^' ''"^''^' i. "'t^PP^^ ^"d '-- «-"« .hin and oSe"y Se;ed thTl"! r'",,"^'".-:"'' ""' P'"^^ »'"• -sometimes locally Uiickened ; the lateral walls with very large, oval pits, chiefly ■> oe. tracheid throughout, rarely , or 3. Bordered pits disti'^ic, y in ,-2 mws numero .;"h";"°»r- '''V '}' *""«^"''=" -='"'' «f ^^e summer wood orermost Su' «■■ ""'" ^"'^ H^T^'^ '^"''"'"' "«' '^""Aned to the outermost walls. Resinous tracheids wanting Tangential. Fusiforrn rays numerous, large, and very broad, the inflated portion compo.sed of rather thin-walled, often strongly resinous cells he raZr n^' "■'"" P'"'«^ ""*• "^'"-"^'"^d epithefiu^m. Ord i^ar riys rather numerous, nonresinous. low to medium, strongly constricted It 312 ANATOMY OF THE OYMNOSPERMS the position of the vei^- narrow and small, interspersed tracheids : the l)arenchyma cells rather equal but variable from broadly to nar- rowly oval, the thin side walls sometimes strongly inflated, rarely incurved. A large tree 46-92 m. hifjh, with a trunk upwards of 7 m. in diameter. Wood very light, soft, oarse, but straight grained, compact, satiny, and easily worked. Specific gravity 0.3684 Percentage of a.sh residue 0.22 Approximate relative fuel value 36.76 Coefficient of elasticity in kilograms on millimeters . . . 794. Ultimate transverse strength in kilograms .... 255. Ultimate resistance to longitudinal crushing in kilograms 5382. Resistance to indentation to 1.27 mm. in kilograms . . 1244. (Sargent) Cascade and Coast Ranges of Oregon, where it descends to 1000 feet above .sea level, from the head of the Mackenzie River and the valley of the Rogue, southward along the western flanks of the California Sierra.s, where it reaches an elevation of 4000-8000 feet ; through the coa.st ranges to the Santa Lucia Mountains, and in the San Bernardino and Cuyamaca mountains (Sargent). 8. P. monticola, D. Don irAi/e Pint Transverse. Growth rings variable. Summer wood open and very thin and imperceptibly passing into the spring wood, the tracheids in regular rows, variable, squarish. Spring wood very open, the tracheids large and squarish, rather thin-walled. Medullary rays prominent and resin- ous, not numerous, rather broad, i cell wide, distant 2-17 rows of tra- cheids. Resin passages very large, rather numerous, the epithelium rather extensive and resinous. Radial. Rays conspicuously resinous throughout, the ray tracheids narrow, marginal, often interspersed. Parenchyma ray cells straight ; the upp«T and loyver walls thin and entire or again with locally numerous, broad pits, unequal ; the terminal walls thin and entire or again locally thick- ened ; the I teral walls with very large, oval or oblong or lenticular pits, chiefly 1-2 per tracheid throughout, in the summer wood reduced to 1 with a lenticular orifice. Bordered pits round or elliptical, in 1 row or sometimes in pairs. Pits on the tangential walls of the summer wood small and narrowly lenticular, chiefly on the outermost wall. Resinous tracheids wanting. Tangential. Fusiform rays not numerous, broad and high, the cells of the inflated portion large and thin-walled, often much broken down. Ordi- nary rays low to medium, strongly resinous, when of a few elements PINUS 3,3 Wood very light, soft, not strong, close and straight grained, and con^pact. Specific gravity Percentage of ash resiuue '. o-39o8 Approximate relative fuel value ° "3 U mate transverse strength in kilograms . . . " Vol' ReZ^llT-''T t«>"«i'"dinal crushing in kilograms c^ln' (Sargem)' '"''"°" '° ''' """' '" •''Wams^ l^l A somewhat uncommon but valuable timber tree, usually below 3000 feet elevation in British Columbia, but rising to 7ooo-.o'ooo fie in cIl of the Fl^head R.ver. northern Montana; south along the Cascade Moun .a.ns of Wash.ng.on and Oregon, and the California Sierras to C la e as B S C^ot\"'^l '''"'''"'" ''''*"'^' ^"^^ ^«"^ -<» Coast rang Bnt..h Columbm. d.sappearing at an elevation of 2235 feet (Macoun) m 9. p. flexiUs, James ^yAite Pine Tran^>erse. Growth rings narrow, rather uniform. Summerwood very thin >-2, or m the marginal cells more rarely 3-4, per frachdd in*^ ht' summer wood reduced to , and lenticular. ^ Bord^eJ pits el'limicar large, in i row, rather numerous. Pits on the taneentiaV wafls oMhi' summer wood numerous and prominent, broadl uSiar esLciallv ortrhydVw'Lrg^'"'^' -^"' ^--"^ ---^riirR^^^^ Ordinary rays numerous, medium, nonresinous, not conScuously I ''' If. 3,4 ANATOMY OK THE C.YMNOSPERMS contracted l>y the sparioKly intcrsijerscd tracheidji ; the cells ef|ual, oval, and uniform, thin-walled ; the lateral walls not concave or convex. A tree 15-18 m. high, with a trunk upwards of 1.20 m. in diameter. Wood lijjht, soft, close grained, and compact. Specific gravity 0-435'* Percentage of ash resid ; 0.2S A|i|'ioximate relative fujl value 43-42 Coetficient of elasticity in kilograms on millimeters . . 676. Ultimate tran.sverse strength in kilograms 266. Ultimate resistance toll n itudinal crushing in kilograms 5591. Resistance to indentation to 1.27 mm. in kilograms . . 1727. (Sargent) Rocky Mountains of British Columbia (Macoun) ; southwai 1 through the Rocky Mountains to Utah, Nevada, New Mexico, and Texas; Inyo Mountains and Mount Silliman, California (Sargent). 10. P. refleza, Engelm. irAtU Pine Transiierse. Growth rinfs variable, often double. Summer wood conspic- uous but thin or upwards of one half the spring wood, from which the transition is gradual, the structure open. Spring tracheids large, scjuar- ish-hexagonal, the walls rather thickish, conspicuously unequal, and often in irregular rows. Medullary rays not very broad, 1 cell wide, distant 2-10 rows of tracheid.s, somewhat prominent; the side walls dI the cells conspicuously inflated and projecting into the adjacent tra- cheid cavities. Resin pa.ssages numerous and large, chiefly in or nc.ir the summer wood; the epithelium composed of large and thin-walled, very resinous cells ; when in the summer wood the resin passage is central to a large tract of thin-walled tracheids. Radial. Rays nonresinous ; the tracheids numerous, low, marginal, and sparingly interspersed. Parenchyma ray cells straight ; the upper -nd lower walls rather thick.sh and entire or again somewhat str ..v'ly pitted, especially in the summer wood ; the terminal walls thin and entire or locally thickened; the lateral wall.s with large, ovil, or s(iuar- ish pits which finally become lenticular, 1-2, chiefly I, pi r traclitid throughout. Bordered pits numerous, elliptical, in I row, distinctly smaller and round toward the summer wood where the orifice beconics a more or less extended slit merging into double striations. Pits on the tangential walls of the summer wood rather small and flat, narnnvly lenticular, chiefly confined to the outermost wall where they are ratlitr numerous. Resinous tracheids wanting. Tangential. Fu.siform rays broad, rather numerou.s, the cells of the intlattd portion very large, thin-walled. Ordinary rays medium to low, not very numerous, nonresinous, rarely contracted by smalle-, interspersed tra cheids ; the parenchyma cells equal, oval, or oblong, the thin side walls strongly inflated, more rarely incurved. FINUS 3,5 Wood I.Kht. hard, n,.t strong, dost- Krainc.l. .,nf a.sh residue . o-4«77 (Sargent) °-f' "* r!^''''*T« '"'';'"'''•■' "' """"" '" '"^■-"''«= -nons at eleva.ion.s Letwcen 6oa.a„d 8000 feet. Hi,i. .ountair,sof southea.s.ern New Mexico. .0 11. • P. strobus, Linn. tf'hU Pint. Weymouth Pine about 8 tracheids, rather con.spicuou.s. variable ind rafh»r^L t me.s double; the tracheid.s .squari.h/une uaHn retSJrows ."h T'"'' s...on from the spring wood Udua'l. Spri^ I'^^'oLr he r^^^^^^^^ large but very unequal tracheid.s distinctlj hexagonal ^dthinVd led Medullary rays not very prominent or broad, . cell wide ew distan; 2-16. or more rarely 30. row.s of tracheid.s. Resin pa^s nume'S', medium, the epithelium .sparingly resinous. t'-'^-''=»>'CS numerous. 'f :, '^^^■■■*. "°"'-«'*i"""«. the tracheids long and low. numerous maririnal and sparmgly interspersed when they are verv low p!,^nM ^ cells straight, equal t';6-.s spring tra^-h^ids^L upper aTdirwaTl^ rather th.ckish and entire or distantly pitted; the t^mlnal wills thin and ent.re or .somewhat locally thickened ; the latera wafls wt h ve v IZ'^^clZ Hord"'-''7'*: '-'r •"'^^^''^ throughout n,ore rare • if^ • , ■ "Offered pits rather numerous in 1 row laru-e sfrnn.rK- elliptical, much reduced, and finally obscure in the suni^erTo'cS whe L- the orihce becomes a prolonged, diagonal slit. I'its on the uTenti ,1 walls o the - ^^ „„^^^^„^ ,^^ ^^,^„_ chiefly narrow yLticu lar Resinous tracheids wanting ' 'cmiLu ^'"'Cnfl fU''^'"''" '-I'' ^""' ""' '•'^'y '^'"^d, nonresinous; the cells of the nflated portion large and thin-walled, often much broken out or fn small branches often wholly wanting. Ordinary rays low to medTum no^ ve y numerous, narrow, nonresinous; the celli equal, ra^h^r unu'^rm oblong, narrow, the side walls rarely convex, more' general b concave!' A large tree of the greatest economic value. 24-52 m. high, with a trunk upwards of 3.50 m. in diameter. Wood light .oft, not strong, very clo.se and straight grained, compact, easily wor' d. and susceptible of a beautiful polish. Specifi gravity Percentage of ash residue . . . °-3«54 Approximate relative fuel value ,0"^ Coeflficient of elasticity in kilograms on millimeters ' ' ' gr , "^^ U timate transverse strength in kilograms . ' ,67 Ultimate : esistarice to longitudinal crushing i„ kilograms 6- lo Resistance to indentation to 1.27 mm. in kilograms , ,qI' (tiargent) ■ . ny^. s mi I. PI ' \ 3l6 ANAIOMY OK THE GYMNOSPERMS The following; determinatinnH are after Uovi-y ; CfK;tTiticnl of {ht JH-T cutiic fiioi . 26 One of the most valuable and '..idely spread trees of Canada, extending frnin Newfoundland, Anticnsti, Nova Scotia, and New Brunswick throuKhoui Quebec and Ontario, and westward nearly to Lake Winnipeg; (Macoun) ; southward through the northern United States to Pennsylvania, the south cm shores of Lake Michigan ; La Salle, Illinois ; Davenport, Iowa ; alonj{ the Allcjjhcny Mountains to northern Georgia (Sargent). Pleistocene deposits of the Don Period, Toronto. Material preserved in natural state, but showing the effects of extended decay. 12. P. panriflora, Sieb. et Zucc. /(;/. = llimtkomatsu Transverse. Growth rings rather broad, the usually thin summer wood up- wards of one half the spring wckxI, from which the transition is gradual. Summer wood rather n\i^\\, often double, the tracheids conspicuously unequal, rounded-he.xagonal. Spring tracheids rather large, s!^- ''^"•"' oval, or broadly lenticular nils ■" ' u ' "^ '■'"'•'' "■'"^«'"' l-'ricc Bordered pits nV^erou C' r ."un.l' in ^' '' ''*'■ '''^'^'"•"l <'-.u«hout. walls of the summer w^';„:,v^ V • ' '"^ ' "^ "" ""■' '^'"^-^n-i^'l chieflyontheoutc^nLt^nKeZ. '?'■'■';"'• .'"'•'^■^ "'"'" "'"' "■"• and promine.-t the r t .Resinous trada-Kls somewhat numerous and sC"in«'sa:i:^.:',;;r"'« '''•''-' """"^'"-- •"•-• -''""->• r-ys U ood I.ght. soft, not strong, brittle, close grained, and compact. Specific gravity Percentage of ash residue 0.41 (-,5 Approximace relative fuel value °"^ CoefTicient of ela.sticity in kilograms ■on'millimc.trs' ' ."f''^"* L t.mate transverse strength in kilograms . ' "• Ultimate resistance to longitudinal crushing in kilograms' C-^Jl Re^.stance to indentation to , .27 n,m. in knograms^ : ' (Sargent) " ■ . i/io. Rocky Mountains of Briti.sh Columbia between 6000 and 7000 feet eleva- tion northward to latitude 53" (Macoun) ; Cascade and Blue mountains of VVashington and Oregon : Scott's Mountain. M,, Shasta, and the high peak.s of the Sierra Nevadas to Mt. San Bernardino. California. Drv, gravelly ndges at the extreme limit of growth, in the San Bernardino Mountains attaining an elevation of ,0.500 feet, and at the highest eleva- tions becoming a prostrate shrub (Sargent). 3i8 ANATOMY OF illK OYMNOSPERMS Section //. Ht$rd Pines 14. P. clauM, Sarg. .SiuHi/ /'/««•. .Sfruh I'lHt. Sfruct Vint Tranrftrst. Growth ritiK* thick, often double. Summer wood dense, rarely Momewhat open, often exceedinx the stprinu wood, from which the tran- itition is usually very abrupt, and within the same section showinK •x)th open and dense structure ; the tracheids rounded, unequal, and often in irregular rows. Spring tracheids hexagonal, not very uniform, the walK rather thickish. Kesin pussaKes larjje, chieHy in the summer wood; the epithelium composed of lar^e, round, and thin-walled cells chictly in I row, occasionally in 2 rows and forminn more or less eccentric tracts. Medullary rays not very prominent or broad, i cell wide, distant 2-8 rows of tracheids. Radial. Rays nonresinous ; the tracheids often predominant and whin interspe ted often l)ccomini{ very low, stronjjly reticulated throuKhoul. Ray cells cf one kind only, the cells rather broad, lonj? fusiform ; the terminal walls thin and entire; the upper and lower walls very thin; the lateral walls with very variable, lenticular, or oval pits, i-s,'chieHy 2-3, per tracheid, in the summer woixl reduced to i. Hordered pits conspicuously i.i 1-2 rows, elliptical, in the summer wood abruptly reduced to 14.4 /i, and finally to 7.2 /i. I'its on the tangential walls of the summer wood wholly wanting. Tanj^cntinl. Fusiform rays medium to hijjh, rather broad; the terminals acute, somewhat prolonged, and compo.sed of few tracheids; the inflated portion composed of very large, rounded, and usually extrenv. ly thin-walled cells among which there may l)c an occasional traeheiii. Ordinary rays numerous and pre.senting three principal ;is{}ects: (1) low rays with large oval, central parenchyma cells and small, terminal tr;i- cheids, fusiform; (2) higher rays composed of large, squarishcelleil and thin-walled parenchy ma, with a few narrower, termin.il tracheids : and (3) the highest rays compo.sed of large, thin-walled, oval, and broad parenchyma cells with small terminal and smaller interspersed tracheids causing local contractions. A tree 21-24 m. high, wii' a trunk upwards of .75 m. in diameter. Wood light, soft, not strong, brittle. Specific gravity ^ -^-f, Percentage of a.sh residue 0.3 1 Approximate relative fuel value \ \ jj.oij Coefficient of ela.sticity in kilograms on millimeters . . 543. Ultimate transverse strength in kilograms 214. Ultimate resistance to longitudinal crushing in kilograms rx528. Resistance to indentation to 1.27 mm. in kilograms . . 2100. (Sargent) Barren, .sandy dunes and ridges of Florida; shores of Pensacola Bay ami southward within 30 miles of the coast to Pea.se Creek ; on the u.ist coast occupying a narrow ridge south of St. Augustine (Sargent). i'lNLS 3,^ 18. P. rigUc, Mill. r,t,M r,n, l)ei;<.inm),' more promineni in rhe low f iv. a'nri i^.i. "-■•u-'M) Of a-n di.s,i„c,ly bordered, or a«ai„ slm^le'^ndt^V a .blt^ Xn ^ Hordcred p„s ,n , r,,w or pairs, dlip.ica). Pits on the tan«cn i "l w^^^^^^ of the hummer wood wholly wantiiiK '-infctntial walls /<7;/^r«/W Fusiform rays not very nun.orojs, rather low and l.roul • .h,. em„nals acute and compo.sed c.f a lew small tracheidl ; ,h ■ celis .V t!. V ru nar> ra)s chiefl> rather low and presenting two principal asix-tts- (0 low rays composed of thin-walled parenchvma much roken ou,' and a few small, terminal tracheids • and r-Thiirh-r r .. * i ' parenchy„,a cells with small, terminal, '^nd fji ' l^^r j r^cLddT the latter causing local contractions. iratncius, A tree .2-24 m. high, with a trunk upwards of .90 m. in diameter W ood light, .soft, not strong, brittle, coarse grained, and con,pact. ' Specific gravity Percentage of ash re.sidue °S'5' Approximate relative fuel value °''^ Coefficient of elasticity in kilograms on millimeters ' ' ' c8i' "'^ Ultimate transverse strength in kilograms ' ' ' ,,/,' Ultimate re.sistance to longitudinal crushing in kilogranis ' cf-Sy' Resistance to indentation to 1.27 mm. in kilograms ' l,.\ (Sarj^eni) *" ■ • • -'-3- Valleyof the St. John River. New Brun.swick. ,0 the northern shores of Lake Ontario (Macoun); south through the Atlantic states to Georijia • westward to the western .slopes of the Allegheny Mountains of VvJst V irginia and Kentucky (Sargent). If .! 320 ANATOMY OF THE GYMNOSPERMS 16. P. MTOtiiu, Michx. Pond Pine. Afarsh Pint Transverse. Growth rings thick. Summer wood dense or in the narrow rings rather open, often exceeding the spring wood, from which the transition is commonly very abrupt ; the tracheids large and not very uniform, hexagonal, in very regular rows. Spring tracheids large, squarish, the walls thin. Resin passages numerous and large, chiefly in the summer wood ; the epithelium in 1 -several rows of very large, round, and dark resinous cells, forming an extensive tract which is often strongly eccentric to the canal. Medullary rays prominent, broad I cell wide, more or less resinous, distant 2-8 rows of tracheids. Radial. Rays more or less resinous throughout ; the tracheids commonly predominant, very variable in height, strongly reticulated throughout sparingly interspersed. Ray cells of one kind only, chiefly rather high more or less fusiform, equal to 4-6 spring tracheids, resinous ; the terminal, upper, and lower walls thin and usually much broken out • the lateral walls with very variable, lenticular pits, 1-4, rarely 5, per tracheid, becoming very narrow and much prolonged slits in the sum- mer wood. Bordered pits in I row or somewhat frequently in pairs, and thus more or less 2-rowed, round, or elliptical. Pits on the tan- gential walls of the summer wood wholly wanting. Tangential. Fusiform rays rather numerous, resinous, narrow, medium to high, the terminals acute, more rarely prolonged, and composed of small tracheids ; the inflated portion composed of large, thin-walled cells usually much broken out. Ordinary rays medium, numerous, broad, resinous, and presenting three principal aspects : ( 1 ) low rays of i-several thin-walled, resinous parenchyma cells with small, termi- nal tracheids ; (2) higher rays chiefly composed of very large, oblong, and often strongly reticulated tracheids with i or 2 large, resinous parenchyma cells much broken out ; and (3) the highest rays of several oblong, resinous parenchyma cells with few terminal tracheids, or again variously contracted through the presence of small, interspersed tracheids. A tree 12-24 m. high, with a trunk upwards of .90 m. in diameter. Wood heavy, soft, not strong, brittle, coarse grained, and compact. Specific gravity ^ ^g ,3 Percentage of ash residue 0,7 Approximate relative fuel value ......... 79.29 Coefficient of elasticity in kilograms on millimeters .11 70." Ultimate transverse strength in kilograms 497. Ultimate resistance to longitudinal crushing in kilograms 8079! Resistance to indentation to 1.27 mm. in kilograms . 4740 (Sargent) An uncommon species in low, peaty soil, ponds, and along the borders nf streams. North Carolina and south near the coast to tli.- head of the St. John's River, Florida (Sargent). PINUS ,^, 17. P. Banksiuu, Lamb. Scrub Pint. Gray Pine. Jack Pme ^''""oTe h^f?h?r"''- ""^' rr°^' ""'^°™- S"'"'"" *ood dense, about tra,-f M^j II "iii-ii waiiea ceil, the whole formine an eccentrir r^ororof'Shei^s;^^ ^"^ '^™=^''' ^°--''- PromLnt!"St '^'^'I'dl^^'.-f''"'"^'^''^"'"''""' *^ ray tracheids strongly predominant R.V n/.I \ T' r ^ '''°"S'>' ^'^''^"lated throughout! fntersZ^j 7««; "='"°^' P--"tin|three p^rin ;h?n,„t^f!i (I) low rays composed of oblong or narrowly oval th,n-walled parenchyma cells with narrowly oblong terminal ra- cheids ; (2) low rays of similar composition, but the parenchTm^ cllU U-ood"l''.'f ^7 "■ "'"• "'" ' ''""' ■■-«')• -"-ding .75 m. in diameter. W ood light, soft, not strong, rather close grained, and compact. Specific gravity ... Percentage of a.sh residue °"}^ Approximate relative fuel value °'^^ Coefficient of elasticity in kilograms on millimeters' ' * 042"^° U timate tran.sverse strength in kilograms ,,« Ultimate resistance to longitudinal crushing in kilograms' 6320 (S^riLn ''°"*°''^ 'S Halifax Nova Scotia, northwesterly to the Athabasca River and down the , Mackenzie River to the Arctic Circle ; eastward it hardly becomes a tree. but westward it increases in size, and westward of Lake Winnipeg i i 322 ANATOMY OF THE GYMNOSPERMS equals the red pine of the east in height and diameter (Macoun) ; south- ward through northern Maine ; at Ferrisburg, Vermont j thence westward along the southern shores of Lake Michigan to central Minnesota. Barren, sandy soil, more rarely in rich loam (Sargent). ¥' w 18. P. contorta, Loud. Strut Pine Tranmerse. Growth rings thick. Summer wood dense, conspicuous, often exceeding (he spring wood ; the tracheids in regular rows, those in the outer portion generally much compressed, variable, those of the central portion more uniform and with rounded lumens; transition from the spring wood gradual. Spring tracheids hexagonal, unequal, in regular rows, the walls rather thin. Resin passages scattering, numerous, small ; the epithelium in 1-3 rows of angular, thin-walled cells which merge outwardly into thicker-walled elements, the whole forming an irregular and somewhat extended tract. Medullary rays rather narrow, I cell wide, not prominent, rather numerous, distant 2-12 rows of tracheids. Radial. Rays nonresinous ; the tracheids numerous, low, sparingly inter- spersed and sometimes predominant, distinctly reticulated throughout. Ray cells of one kind only and variously fusiform; the terminal, upper, and lower walls very thin and often much broken out or wholly wanting ; the lateral walls with large, oblong, or lenticular pits which often become round or oval when the ray is only i cell high, and on the inner face of the spring wood in all rays, 1-4, chiefly 2-3, per tracheid, in the summer wood greatly reduced in size, shape, and number. Bordered pits in i row, sometimes in pairs, elliptical, becoming much reduced and remote in the summer wood. Pits on the tangential walls of the summer wood wholly wanting. Tangential. Fusiform rays not numerous, medium ; the terminals acute, rarely somewhat prolonged, and composed of small tracheids ; the cells of the inflated portion all very thin-walled and generally broken out. Ordinary rays medium, rather numerous, the thin-walled parenchyma cells predominant, commonly broken out so as to leave the ray vacant for nearly the whole height, the tracheids ch:..'iy terminal but occa- sionally interspersed as somewhat narrower and rounded elements, causing local but slight contraction. A small, stunted tree 6-9 m. high, with a trunk upwards of .50 m. in diameter. Wood light, hard, strong, brittle, and coarse grained. Specific gravity 0.5815 Percentage of ash residue o.ig Approximate relative fuel value 58.04 Coefficient of elasticity in kilograms on millimeters . . 1585. Ultimate tran.sverse strength in kilograms 423. Ultimate resistance to longitudinal crushing in kilograms 8868. Resistance to indentation to 1.27 mm. in kilograms . . 2382. (Sargent) Columbia along the coast to m!!V ^ southward from British 19. P. glabra, Walt. CtJar Pine, spruce Pine. Whitt Pine ""TriSw^o^lmThiJfthe t'""^" ^^ '' ^^"» o- l-alf the doubfe or treb!nhe"Srl?;orr„''de"n;: "1?'?.^°"'^*'^^* ='''^"P'' especially when double or trehll tKl ? 'u •!■ °"'^'' Po^'ons open, regular rows. Spring tracheidshiv, t'^''^ -I" ""^" ^^"^^le, in the walls thin. K ptos "^hT"!' "i?'^""" '" ^^S'"^'" ^«>w«. thelium in 1-2 rows of C^r^ J !' abundant, medium; the epi- irregular cells usurnymuc7b;oK^ Tf ";'"-^."ed. resinous and tracts. Medullary rays no'ver? broad nromi?. °'''^'"« ^^""^ "'^"'^^'^ 2-12 rows of tracheids ^ ' P'^"'""'^'". ^^ numerous, distant and becoming rshmsm^'^*^:^^^^ finally reduced to summerwood%oonrSuce^itOQ6 'S/n fi" ' J?^^' ^"iP'ical, in the aspects: 0) r"-. S^ T, ' '1"^ ^•••"linS l»o principa] c«po.rt „, |„g;, toSeTpLSZl SL S 7^ ■'=*, ">3 interspersed, chiefly DrpHomino„» J ^ *"*" termmal and contraction ^ P«dom.nant and narrower, tracheids causing local wi'cJiltf w; "^^ ""'' ' '™"' "P^^^*^-^ ''^ '-^^ >"• '■" diameter. Wood hght, soft, not strong, brittle, very coarse grained, not durable. Specific gravity Percentage of ash residue °-393i Approximate relative fuel value °''5 1^1^ Jr i :11 mm 324 ANATOMY OF THE GYMNOSPERMS South Carolina to the Chattahoochee region of Florida, chiefly near the coast, thence through the Gulf States south to latitude 32° 30' to the valley of the Pearl River, Louisiana, iu greatest development being ii. Alabama and Mississippi (Sargent). ii« • I'* 20. P. echinaU, Mill. Ytllow Pine. Short-Leaved Pine Transtitrse. Growth rings thick. Summer wood thick, very prominent, dense, and often exceeding the spring wood from which the transi- tion is generally very abrupt ; the tracheids unequal in regular rows, but varying greatly in different growth rings so that the structure pres-nts a very variable density. Spring tracheids large, squarish- hexagonal, the walls thin. Resin passages numerous but large and scattering; the epithelium composed of i row of thin-walled cells, less frequently becoming 2-rowed in part, the cells often resinous. Medul- lary rays prominent, rather broad, numerous, distant 2-8 rows of tracheids. Radial. Rays somewhat resinous throughout; the ray tracheids rather high, conspicuously predominant and very strongly reticulated through- out, often composing the entire ray. Ray cells of one kind, rarely of two kinds, few, interspersed, fusiform ; ti..' terminal, upper, and lower walls very thin and much broken out ; the lateral walls with very variable, lenticular pits, 1-4 per tracheid, becoming more or less obso- lete in the summer wood. Bordered pits in i row or pairs, rarely 2-rowed, elliptisal, in the summer wooid reduced to 7.2 /i, when the orifice often becomes obscure or eccentric. Pits on the tangential walls of the summer wood wholly wanting. Tangential. Fusiform rays rather numerous, high, the terminals prolonged, linear, and composed of broad parenchyma cells with terminal tra- cheids ; the cells of the inflated portion very thin-walled and usually all broken out. Ordinary rays rather numerous, high, presenting two principal aspects: (i) low rays composed of thin-walled parenchyma much broken out, and small, terminal tracheids ; and (2) higher rays composed of oblong tracheids with few, interspersed, broader cells of thin-walled parenchyma, thus causing local expansions. A tree 24-30 m. in height, with a trunk upwards of 1.35 m. in diameter. Wood varying greatly, heavy, hard, strong, generally coarse grained, and compact. Specific gravity 0.6104 Percentage of ash residue 0-29 Approximate relative fuel value 60.86 Coefficient of elasticity in kilograms on millimeters . . I37S- Ultimate transverse strength in kilograms 443- Ultimate resistance to longitudinal crushing in kilograms 7628. Resistance to indentation to 1.27 mm. in kilograms . . 2064. (Sargent) PINUS 325 Staten Island, New York, thence southward to western Florida and throujjh the Gulf States to Tennessee and eastern Texas; thrru^h Arkansas to Oklahoma; southeastern Kansas, southern Missouri, and in Union County, Illinois (Sargent). 21. P. reainou, Ait. Red Pine. Norway Pint 7><7««/' *''''='' •'"' variable, often double. Summer wood hu. of about 4-«o tracheids but very variaL'e, usually v^ry open ; the tracheids very unequal, now small and round or again large and much compressed, often in very irregular rows ; transition from the spring wood somewhat gradual. Spring tracheids arge, hexagonal uniform, m regular rows, the walls thin. Re.sin passages verXge rather abundant; the epithelium in 2 rows, that next The canil con^! posed of large and rather thin-walled cells which are immediately bounded by a layer of rather thick-walled, large, rounded, and often resinous cells. Medullary rays broad, . cell wide, rather prominent" sparingly and ocally resinous, distant 2-.0 rows of tracheids. ' kadial Rays locally resinous; the ray tracheids strongly predominant, strongly dentate, and somewhat reticulated in the summer wood. Ray w^in?r"fM^-"^°T ^"'^ •'^ '^^ '''"'•^= (') ^'''her numerous, the terminal walls thin and entire ; the upper and lower walls rather thick and very coarsely pitted ; the lateral walls with variously oval, oblong, mer'wooH '. ^^.'k' '"ll "^"'''^ ^' ^' *^=''=*'^''*' becoming 2 in 'the sum^ mer wood ; (2) the cells equal to about 5 spring tracheids, the terminal Mi« if '^T'^ ; the upper and lower walls thin and entire ; the lateral walls with oval, oblong, or round pits, 2-4, chiefly 4, pe^ tra- cheid, becoming 2 in the summer wood. Bordered pits in i row sometimes in pairs, often numerous, elliptical. Pits on the tangential walls of the summer wood wholly wanting. 330 ANATOMY OF THE GYMNOSPERMS TaHi'tnlial. Fusiform rayn rather numerous and narrow, the terminals somewhat prolonKcd but rather broad, the cells of the inflated portion rather thick-walled, those of the terminals lar;" and thin-wallccl. Ordinary rays rather numerous, low to medium, much narrowed l.y the numerous and very variable, interspersed, and predominant tra cheids; the relatively few parenchyma cells often resinous, very unequal and variable, oval, both thick- and thin-walled, the latter often much broken out. A large tree 61-91 m. high, with a trunk 3.60-4.57 m. in diameter. Wood variable in quality and value, hard, heavy, strong, brittle, not coarse grained nor durable, compact. Specific gravity 0-4715 Percentage of ash residue °-35 Approximate relative fuel value ^^° Coefficient of elasticity in kilograms on millimeters . . 824- Ultimate transverse strength in kilograms 279' Ultimate resistance to longitudinal crushing in kilograms 6292. Resistance to indentation to 1.27 mm. in kilograms . . 1740. (Sargent) Interior of British Columbia south of latitude 51", thence southward along the mountain ranges of the Paci'ic region to Mexico ; eastward to liie Black HilLs of Dakota, Colorado, and western Texas. Dry, rocky ridKcs and prairies, or in the northern portion of California, rarely in cold, wet swamps, reaching its greatest development on the western slopes of the California Sierras (Sargent). 27. P. Coulttri, D. Don Pitch Pint Tranmtrse. Growth rings thick, variable. Summer wood thin, upwards of 10 tracheids and open, the transition gradual ; the tracheids very- vari- able, inded, and often much compressed, in conspicuously irregular row; pring tracheids large, squarish-hexagonal, the walls ratlier thi: Xesin passages rather abundant, medium; the epithelium in 1- ■■■■: eral rows of large, rather thick-walled, and chiefly rounded cells, no. csinous, often forming extensive and irregular tracts about tlie canal. Medullary rays broad, i cell wide, rather prominent, distant 2-20 rows of tracheids. fiAdial. Rays sparingly resinous throughout ; the tracheids low, often pre- dominant, nwre or less reticulated throughout, and often composing the entire structure in low rays. Parenchyma cells fusiform, of two kinds: (i) high and prominent, especially in the low rays; the ter- minal walls thin and not pitted; the upper and lower walls thick and coarsely pitted ; the lateral walls with round or oval and prominent pits, 1-4, more rarely 6, per tracheid, becoming 1-2 in the summer wood; and (2) the cells fusiform, the terminal walls thin and not pitted ; the upper and lower walls very thin, often much broken out, or auun PINUS 33, ateral wa I, w.th oval or lenticular pitn. ,-3. chicflv 2. per trachei.l .hrouKhout. very unequal and variable in form ancf siie Ikirdert-.l pits in I row. sometimes in pair», elliptical. InJcominR greatly re- duced in the Kummer wood, and fin^giy wantinK, J'itn on the tanRent .1 walls of the summer wood wholly wanting lanKenii.u langeHhal. Fusiform rays rather numerous, medium, narrow ; the acute or «NTSriffl,/T'"^''" "''""'' T*'""'''^""'^^^ °f tracheidn; the cells of the inflated portior vtry thin-walled and usually broken out Ordinary rays rather numerous, low to high, nonresinous and presentini,' l„H^Kf''^""'^f'/"'^'^'''L <■>'*'* ">" *»'°"y ^"mposed of tracheidt and thick-walled parenchyma cells, rarely 2-^riate at least in part; m.lh T I rays w„h, he thin-walled parenchyma of the central portion much broken out. and showing an interspersed thick-walled paren- tlwlln r" •*"= ""''^^! »"d (3) .-seriate rays chiefly composed of hin-walled parenchyma terminated above and below by thick-walled cells and tracneids. tl^u^:f^ "I: '*'*''*'• *"'' "."■""*' upwards of 1.80 m. in diameter. Wood light, soft, not strong, brittle, and coarse grained. Specific gravity Percentage of ash residue ...... o t?^^ Approximate relative fuel value . . . . . ' ' 4,,8 Coefficient of elasticity in kilograms on miilim'eter;, " lui" Ultimata transverse strength in kilograms . ,,/ Ultimate resistance to longitudinal crushing in kilograms 587a Resistance to indentation to 1.27 mm. in kilograms ^A^T (Sargent) " ^"' The Coast Range of California, most abundant and attaining its greatest development in the San Jacinto Mountains (Sargent). s i 28. P. tuberailau, Gord. KiiohCone Pine Transverse. Growth rings thick. Summer wood prominent, open, upwards of equal to the spring wood ; the tracheids very unequal in regular rows, distinctly rounded, or the outermost more or less compressed and with much thmner walls ; the transition from the spring wood gradual. Spring tracheids hexagonal, .somewhat variable, in regular rows, the walls thin. Resin passages rather numerous, chiefly in the summer wood, scattering, large ; the epithelium in 1-3 rows of large and very thin-walled and resinous cells which form a more or less extended tract and often merge into thitker-walled parenchyma or thin- walled tracheids. Medullary rays rather broad. 1 cell widt-, not prom- ment, sparingly and locally resinous, di.stant 2-15 rows of tracheids. Kadtal. Rays .sparingly and locally resinous, the resin ma.ssivc ; the ray tracheids about equal to the parenchyma cells, sometimes predominant and interspersed, the upper and lower walls dentate, more or less reticulated throughout. Ray cells of two kinds: (1) thick-walled ft 332 ANATOMY OF THK (IVMNOSPKRMS nomcwhat (usiform cells chiefly c(iii li, the terminals chiefly acute, rarely somewhat prolonged : the intlated portion wholly compo.scd of very thin-walled cells which are commonly broken out. Ordinary rays medium, rather numerous and vcrv broiid, pres* iitinK three principal aspects: (i) low rays wholly composed of terminal tracheids and ihin-walleil. resinous parenchyma comninnly broken out ; (2) higher rays composed of very thin-wali'd, resinnwi.s piirenchyma much broken out, with terminal, interspers. 4 and predominant, small tracheids which cause local contraction ; aiul (3) low rays composed of tracheids with I centra!, thick-walled paren- chyma cell. A tree 18-22 m. hi>{h, with a trunk upwards of .90 m. m diameter. Wood light, .soft, not strong, brittle, coarse grained, and compact. Specific gravity . • <3-3499 Perccnta^'e of ash residue . . 0.33 Approximate relative fuel value 34**''* Coefficient i>f elasticity in kilograms "n millimelcf . 429. Uliimate transverse strens{ih in kilogiams 175 Ultimate resistance to longitudinal crushing in kilograms 4207. Resistance to indentation to I. .;7 mm. in kilograms . . 1372- (Sargent) Dry, gravelly ridges and slopes, not lom ion, 2500-5000 feet eleva- tion. Valley of the Mackenzie River. Ore);>'ii. and southward alonir the slopes of the Cascade and Sierra N cvada mountains, and in the California Coast Range from Santa Cruz to the San Jacinto Mountains (Sargent). 29. P. TotreytUft, Torr. SoltiltiJ Pint Transverse. Growth rings variable, tfie structure showing a marked tend- ency to radi.il fracture. Summer wood prominent but rather optn, about one :hird the spring wood, (torn which the transition is aluLpl when thin, ut when thicker the transitibn is often gradual both v !\s; the tracheids large, squarish, and often in irregul.i. row ■<. prmg tracheids large, squari^ rather uniform in regular rows, the ".ills medium. Resin passages scattering, median: ; the epithelium ci'm- posed of larK' ■ thin-walled, irregular and resinous ceils in 1-3 rows, PINUS 333 r£Mn',H '"n ''"^If ..*""' ■*"*' ""'^s^lly l>»" inlo occasional K' Hut ." • "«*"' "y '»>" broad. , cell wide. m,. very prom- inent, distant 2-10 rows of trachcid.1. Radial. Ray> .paringly resinous, the resin confined to the thin walls • ihe iracheid. about equal to. or in the low rays exceeding, the pare "chym! cell.; rarely interspersed. MronKlv reticulated throughout SccH^^'s walls thin and entire ; the upper and lower walls thick c« .rs^lv Ind Imperfectly p tted , the lateral walls with very prominen and mund elliptical or oblong pits which sometimes lK.cnn,e distinclirilrdrnd n he summer w«>«d, 2-4, chierty 4, per tracheid , and (2) celN oid Ind m?;h*I!'* r*''".'"^" ' "'V'^^'"'""'' "P»^'- and'lower w Is very "hi* n paTrs TlK' al'in^.hJ'"''''' "°1""* P"" '" ' -- -"'clme: i^c n P • '" "^* summer wood quickly reduced to 1-.-IJ .. rhoif; waVt;;^:^ "■ ^'" "- "^^ '»"«-"'• -"^ «' '•'^- --- :t(s TaHgtHtiai. Fusiform rays rather numerous. s,nall to mer'ium. the (.rminals herJh't.'Vh^^ •':?'"7'-:' '"'°"«^*'' "^"^■" "«»'«' fo .he "hole height ; th.- tells of ,he terminals compc.a-,i of thick-walitd r.aren chymaand small a. (.ids. those of the inriated |K,rtion v.ry mm- waled and generally t,roken out. Ordinary rays low "o mediu somewhat numero. broad, very r;K.ly contracted by the smaM and r: uch narrower, mtcrspersed tracl>. kIs of the highest rays hk * ailed parenchyma cells few , thin-walled parenchyma oHs predon ■" injr t. resinous, much broken ou^ jjicuum A low, .^ort-lived, gnaric :, and cro...cd tree 6-8 m. hi^h, «i,h a trunk upwards of .33 m. in diameter. Wood light, soft, not strong, britti, . ra.ne. clo.se grained, and comp.ict. Specific gravity ... Percentage of a.sl residu. ..." 0-4879 Approximate rtla .e fuel value °f ' Coefficient of cla>L.ity in kilogram.s t miliinuurs' .' ' A°' '' t. mate transvers. Mrength in kilograms . ,;; ulS" '''•■*""'^'-" '° '■ '"nz wood rather aljrupt ; the tracheids in regular n.., variable bprn , tracheids squarish-hexagonal, very uncj^al in reg^Iarrows' IK' ■'i'- 334 ANATOMY OF THE GYMNOSPERMS the walls rather thin. Resin passages very round, large, somewhat numerous ; the epithelium cells at first flattened and rather thin-walled, quickly passing into large, rounded, thick-walled, and strongly resinous wood-parenchyma cells which often form extensive and somewhat irregular tracts. Medullary rays prominent, resinous, broad, i cell wide, distant 2-10 rows of tracheids. Radial. Rays locally and strongly resinous, the resin massive ; the ray tracheids low, marginal, and interspersed, often predominant, strongly dentate and sparingly reticulated in the summer wood. Ray cells of two kinds, but merging and not always -learly distinguishable: (1) thick-walled, fusiform cells ; the terminal walls thin and locally thick- ened ; the upper and lower walls coarsely pitted ; the lateral walls with very variable, oval, or lenticular pits, 2-4, chiefly 3, per tracheid, becoming 1 in the summer wood ; and (2) thin-walled, fusiform cells ; the terminal, upper, and lower walls thin and not pitted, the former often locally thickened ; the lateral walls with lenticular, chiefly narrow and simple pits, 2-4 per tracheid, becoming 1-2 in the summer wood. Bordered pits in 1 row, sometines in pairs, elliptical, becoming smaller toward the summer wood, where they are finally obscure. Pits on the tangential walls of the summer wood wholly wanting. Tangential. Fusiform rays rather numerous, low, variable, rather broad and unsymmetrical ; the terminals acute or prolonged ; the cells vari- able, chiefly thick-walled throughout, often resinous. Ordinary rays low, numerous, resinous, and strongly contracted by the frequently interspersed and much narrower tracheids ; the parenchyma cells of two kinds: (i) thick-walled cells chiefly predominant; and (2) thin- walled cells more or less broken out, interspersed. A small tree 18-24 m. high, with a trunk upwards of .4S-.60 m. in diameter Wood light, soft, strong, brittle, close grained, and compact. Specific gravity 0.5457 Percentage of ash residue 0.39 Approximate relative fuel value 54-37 Coefficient of elasticity in kilograms on millimeters . . 726. Ultimate transverse strength in kilograms 355. Ultimate resistance to longitudinal crushing in kilograms 5398. Resistance to indentation to 1.27 mm. in kilograms . . 2470. (Sargent) Dry, rocky ridges and slopes between 5000 and 7000 feet elevation Arizona, New Mexico, and Chihuahua, Mexico, not common (Sargent). 31. P. Jeffre]rl> A. Murr. Hull Pine. Bla(k Pine Transverse. Growth rings narrow, rather uniform. Summer wood tliin and open, or again very thin and very open ; the tracheids uniform in regular rows, more rarely unequal in irregular rows ; the transition from the spring wood rather gradual. Spring tracheids large, hexagonal, PINUS 335 very unequal in regular rows, the walls rather thin. Resin passaees large, scattering; the epithelium composed of very large, rounded, rather thin-walled and variable cells in 1-3 rows, often forming rather large tracU. Medullary rays broad, i cell wide, not very prominent, distant 2-i6 rows of tracheids. Radial. Rays nonresinous ; the tracheids strongly dentate and more or less reticulated throughout, numerous and strongly predominant Ray cells of two kinds: (1) thick-walled cells prominent, fusiform, equal to about s spnng tracheids ; the terminal walls locally thickened -the upper and lower walls strongly thickened and pitted ; the lateral walls with prominent, round pits, 2-5, chiefly 3-4, per tracheid, conter- minous with and merging into the cells of the second order; and (2) fusiform cells equal to about 5 spring tracheids; the terminal walls thin and not locally thickened ; the upper and lower walls thin and entire or more rarely locally thickened; the lateral walls with lenticular or oval, very variable pits, 1-4 per tracheid. Bordered pits in I row, sometimes in pairs, elliptical, becoming quickly reduced in the summer wood, and finally 7.2 /*. Pits on the tangential walls of the summer wood wholly wanting. Tangential. Fusiform rays few, medium, the terminals acute or somewhat prolonged; the cells of the inflated portion large and thin-walled, usually much broken out. Ordinary rays rather numerous, medium to high, nonresinous, chiefly composed of narrow tracheids with inter- spersed and much broader parenchyma cells. Parenchyma cells of two kinds: (1) thick-walled cells which predominate in low rays, becoming interspersed in high rays ; and (2) the usually broader, more squarish, and thin-walled cells. A large tree 30-31 m. high, with a trunk upwards of 4 m. in diameter. Wood light, strong, hard, rather coarse grained, and compact. Specific gravity 0.5206 Percentage of ash residue o 26 Approximate relative fuel value . . . eoiss Coefficient of elasticity in kilograms on millimeters . '. '. 925! Ultimate transverse strength in kilograms 318. Ultimate resistance to longitudinal crushing in kilograms 6679! Resistance to indentation to 1.27 mm. in kilograms . . . 1850. (Sargent) Drj-, gravelly slopes between 6000 and 8000 feet elevation. Along the Sierra Nevadas of California from Siskiyou Mountains to the San Ber- nardino and San Jacinto mountains (Sargent). 32. P. ponderosa, Lawson y*/low Pint. Bull Pine Transverse. Growth rings thin, variable. Summer wood variable, dense, sometimes open, the transition from th. spring wood often abrupt; the tracheids round-hexagonal, unequal, and in somewhat irregular rows. 336 ANATOMY OF THE GYMNOSPERMS Spring tracheids squarish-hexagonal, variable, in somewhat regular rows, rather thick-walled. Resin passages medium, numerous, chiefly in the summer wood ; the epithelium in 1-3 rows of rather large and verj- thin-walled cells, succeeded by thick-walled elements, the whole forming a somewhat extended tract which commonly breaks out in making tran.s- vers«: sections. Medullary rays very broad, i cell wide, nonresinous, not numerous, distant 2-15, or sometimes 20 rows of tracheids. Radial. Kays nonresinous ; the tracheids predominant or equal to the paren- chyma cells, and usually strongly reticulated. Parenchyma cells of two kinds : ( I ) rather few ; the terminal walls thin and locally thickened ; the upper aaJ lower walls rather thick hut not very strongly pitted ; the lateral walls with very conspicuous, tound or lenticular, very vari- able pits, 2-4, rarely 5, per tracheid ; and (2) variously contracted cells, the terminal, upper, and lower walls thin and entire ; the lateral walls with lenticular or oval pits, 1-4 per tracheid. Bordered pits in i row, round or more generally elliptical. Pits on the tangential walls of the summer wood wholly wanting. Tangential. Fusiform rays somewhat numerous, low to medium ; the termi- nals acute, composed wholly of tracheids ; the cells of the inflated por- tion very thin-walled and usually broken out. Ordinary rays low, numerous, nonresinous; the tracheids chiefly terminal or when inter- spersed causing a slight contraction ; the thick-walled parenchyma cells chiefly termini, few, the thin-walled parenchyma occupying the central region and forming the greater portion of the ray, generally broken out, the cells oval, variable. A large tree 61-91 ™- >" height, with a trunk upwards of 4.57 m. in diameter. Wood varying greatly in quality and value, heavy, hard, strong, brittle, not coarse grained or durable, compact. Specific gravity 0.4715 Percentage of ash residue 0.35 Approximate relative fuel value 46.99 Coefficient of elasticity in kilograms on millimeters . . . 887. Ultimate transverse strength in kilograms 307. Ultimate resistance to longitudinal crushing in kilograms 6037. Resistance to indentation to 1.27 mm. in kilograms . . . 17 19. (Sargent) Interior of British Columbia south of latitude 5 1°, south and east along the mountains of the Pacific region to Mexico, the Black Hills of Dakota, Colorado, and western Texas. Dry, rocky ridges; rarely in cold, wet swamps, reaching its greatest development on the western slope of tlie California Sierras. After Pseudotsuga Douglasii, the most generally dis- tributed and most valuable timber tree of the Pacific forests (Sargent). The distribution of this species and the qualities of the wocJ are not clearly separable from the next species. PINUS 33- 33. P. Bcopakmim, Lemmon ^''"'i^^rse Summtr wood very variable, rather open, commonly double: the tracheids m very regular rows and uniform, but generaUy much com- pressed; the transition from the spring wood rather abrupt. Sprine tracheids conspicuously squarish, rather uniform in regular rows, lard and thin-walled Resin passages rather numerous and scattering not large ; the epithelium nonresinous, composed of about 2 rows of verv large and very thin-walled ceUs, those of the limiting layer flattened r5!!f/i 'f*=°"*^*T, l»y«« "-ound, merging into a few thick-walied! round parenchyina cells on the borders of the wood tracheids Medul' Sllf/,' ? " ^'°'^' / "" ''**'*'■ '''•'" """""""^ but not prominent, distant 2-10, more rarely 1 7, rows of tracheids. Hadia^ Rays nonresinous ; the ray tracheids commonly high, marginal, or r^tirZ^n'^TP*^"^,*^ '^ "^^ "J'-S*"" "^y'- P-^dominant knd sparingly locally thickened ; the upper and lower walls thick and strongly pitted ; the lateral walls with round, simple pits 1-4 per tracheid, conteminous and interspersed with those of the second order; and (2) the terminal upper and lower walls thin and not pitted or locally thickened ; the hiteral walls with small, lenticular pit.s, 2-4, chiefly 4, per tracheid, becoming i or 2 in the summer wood. Bordered pits in i row numerous, crowded, elliptical. Pits on the tangential walls of the summer wood wholly wanting. Tangential. Fusiform rays not numerous, narrow ; the somewhat prolonged terminals composed of tracheids ; the inflated portion composed of v^r>- thm-walled cells, usually all broken out. Ordinary rays rather numerous^ low to medium, nonresinous, conspicuously contracted by the somewhat narrower, sometimes interspersed, and conspicuously predominant tra- cheids; the thick-walled parenchy-ma cells few, not prominent, the thin- waued parenchyma cells occupying the central tract, oval, variable. 34. P. pungens, Michx. f. Table Mountain Pint. Hickory Pint Transverse. Growth rings thick. Summer wood ver>- prominent, dense or sometimes somewhat open, often double, the transition from the spring wood gradual, sometimes abrupt ; the tracheids in regular rows, vari- able, rounded. Spring tracheids strongly hexagonal, verv- unequal in regular rows, the walls rather thick. Resin passages rather large, numerous, chiefly in the summer wood; the epithelium in i row of veiy thm-walled and nonresinous cells, rarely much exceeding the canal and forming eccentric tracts of limited extent. Medullary rays rather it. V / o' ^""^what prominent, numerou.s, distant 2-15 rows of tracheids Kadtal. Rays somewhat resinous throughout ; the tracheids variable, often predominant, reticvlated tliroughout and more or less interspersed Ray cells of two kind.> : ( i ) cells numerous and long fusiform ; the ter- minal walls entire or locally thickened : the upper and lower walls strongly thickened and coarsely pitted ; the lateral walls with very vari- able, oval, or lenticular pits, 1-3 per tracheid, in the summer wood distincUy bordered, the orifice a prolonged slit ; and (2) cells variously w '■ M y f \ M&l 1 338 ANATOMY OF THE GYMNOSPERMS fusiform, the terminal, upper, and lower walls thin and usually much broken out; the lateral walls with lenticular or oval, very variable pits, 1-4, chiefly 2 or 3, per tracheid, in the summer wood becoming distinctly bordered, the orifice an extended slit, conterminous with tracheids and cells of the first order. Bordered pits in I row or pairs, elliptical, and toward the summer wood soon replaced by narrow slits, which often lead into strong, double striations. Pits on the tangential walls of the summer wood wholly wanting. Tangential. Fusiform rays not numerous, low and broad, the chiefly acute terminals composed of a few tracheids ; the cells of the inflated portion very thin-walled, chiefly broken out, or again rather thick-walled in part and pwrsistent. Ordinary rays low to medium and presenting four prin- cipal aspects : ( I ) low rays of thin-walled parenchyma, much broken out, and small, terminal tracheids ; (2) low rays of thick-walled parenchyma and small, terminal tracheids ; (3) higher rays of thick-walled paren- chyma and both terminal and interspersed tracheids with occasional thin-walled parenchyma; and (4) the highest rays of thin-walled, resin- ous, and interspersed thick-walled parenchyma, together with terminal and interspersed tracheids. A tree 9-18 m. high, with a trunk upwards of t.05 m. in diameter. Wood light, soft, not strong, brittle, coarse grained, and compact. Specific gravity 0-4935 Percentage of ash residue 0.27 Approximate relative fuel value 49-22 Coefficient of elasticity in kilograms on millimeters . . 803. jltimate tran.sverse strength in kilograms 310. Ultimate resistance to longitudinal crushing in kilograms 5670. Resistance to indentation to 1.27 mm. in kilograms . . . 1842. (Sargent) Allegheny Mountains, Pennsylvania to Tennessee, in the high moimtains of the latter attaining its greatest development (Sargent). 35. P. inops, Ait. Jersey Pine. Scrub Pine Transverse. Growth rings thick, often double. Summer wood rather dense, sometimes more or less open, equal to about one fourth or one third the spring wood, from which the transition is usually abrupt ; the tracheids strongly unequal, chiefly in regular rows. Spring tracheids squarish, large, very uniform in regular rows, the walls thin. Resin passajjes rather numerous, medium; the epithelium in 1-2 rows of large, round, thin-walled or again rather thick-walled, resinous cells, which are often developed eccentrically about the canal, and become thicker-walled especially on the outer limits. Medullary rays prominent, rather broad, I cell wide, not numerous, distant 2-12 rows of tracheids Radial. Rays somewhat resinous, the resin massive, localized ; the tracheids numerous low, very variable and verj' strongly reticulated throughout, predominant, often.interspersed. Ray cells of two kinds : ( i ) the terminal PINLS 339 walls thin and locally thickened; the upper and lower walls more or less thickened and coarsely pitted ; the lateral walls with lenticular or oval, variable pits, 2-6 chiefly 4, per tracheid, finally becoming slit- like and reduced to i in the summer wood or eventually obsolete, often conterminous with tracheids or with thin-walled parenchyma cells: and (2) the predominant elements ; the terminal, upper, and lower walls thin : the ateral w^ls with very variable, oval, or lenticular pits, 1-4 or more rarely 5 chiefly 4, per tracheid, in the summer wood merging into pro lonpd shts or final y into round, bordered pits with an oblong, narrow orifice; fusiform, chiefly high. Bordered pits in i row or paiw, ellip- tical, becoming round and conspicuously smaller toward the silmmer wood, where they are finally reduced to 72 ^. Pits on the tangential walls of the summer wood wholly wanting. Tangential. Fusiform rays medium, rather few, narrow ; the terminals acute and composed of large and small tracheids; the inflated portion com- posed of thin-walled tissue, much broken out and more or less resinou.s Ordinary rays chiefly low and presenting three principal aspects- f 1) low rays distincdy fusiform, with a large tracheid in the center and small terminal tracheids; (2) higher rays of i-several large, thin-walled, and resinous cells, much broken out, with or without interspersed thick- walled cells, sometimes in pairs, and terminal tracheids of variable size; and (3) the highest rays composed of large, thin-walled paren- chyma cells, often with resin, but usually much broken out, terminal tracheids and i-several small, interspersed tracheids, causing local contractions. * A tree 24-36 m. high, with a trunk upwards of .90 m. in diameter. Wood light, soft, not strong, britUe, very close grained, compact, and durable. Specific gravity ^ Percentage of ash residue ' o'w Approximate relative fuel value .......' 52 q» Coeflicient of ela.sticity in kilograms on millimeters '. ' ' cL Ultimate transverse strength in kilograms .... 281 Ultimate resistance to longitudinal crushing in kilograms 5765 Resistance to indentation to 1.27 mm. in kilograms . . 2406' (Sargent) ^^' Sandy, generally barren soil. Long and Staten islands. New York ; south- ward usually near the coast to South Carolina and westward through eastern and middle Kentucky to southeastern Indiana (Sargent). 86. P. mur Jita, D. Don I'lkkle-Couc /'hie Transverse. Growth rings thick. Summer wood prominent but rather thin about one fifth the spring wood, variable, both dense and open • the tracheids variable, in the open zones often much compressed and in irregular rows, the walls variable ; the transition from the spring wo,)d rather gradual. Spring tracheids hexagonal, unequal, in regular rows ! 1 n ^\ 1 A,. 340 ANATOMY OF THE GYMNOSPERMS the walls rather thin. Resin passages scattering, rather small, somewhat numerous, chiefly in the summer wood; the epithelium in 1-2 rows of large, rounded, ':hin-walled, often strongly resinous cells, which some- times become thick-walled at the outer limits. Medullary rays not numerous or prominent, rather narrow, i cell wide, distant 2-30 rows of tracheids. Radial. Rays locally somewhat resinous, the resin massive; the ray tra- cheids strongly predominant, often composing the entire structure of the low rays, in the higher rays marginal, more rarely interspersed, reticulated in the summer wood. Ray cells of two kinds : ' (i) rather frequent but not predominant except in the low rays, rather high and long fusiform ; the terminal walls thin, sometimes strongly pitted ; the upper and lower walls rather thick and coarsely pitted ; the lateral walls with prominent and very variable, oval, round, or lenticular pits, 1-4 per tracheid; and (2) cells resinous, the terminal, upper, and lower walls thin and much broken out; the lateral walls with lenticular pite 1-3, chiefly 2, per tracheid. Bordered pits in i row, sometimes in pairs, numerou.s, elliptical. Pits on the tangential walls of the summer wood wholly wanting. Tangential. Fusiform rays low, the terminals acute, rarely prolonged ; the cells of the inflated portion large and rather thin-walled, often wholly broken out. Ordinary rays low, rather broad, the cells very variable in shape from oval to squarish, and presenting four principal aspects : ( 1 ) low, fusiform in shape, composed of thick-walled, oval parenchyma cells with terminal tracheids ; also higher rays of the same a.spect ; (2) low rays of thick- and thin-walled, oval parenchyma — the latter resinous, but otherwise not very different — and small, terminal tracheids; (3) higher rays of large, broad, thin-walled, resinous parenchyma, 1-2 thick- walled parenchyma cells and terminal tracheids; and (4) the highest rays of thick-walled parenchyma and interspersed tracheids with local contractions. Parenchyma cells oval, very narrow. A tree 24-36 m. high, with a trunk upwards of .90 m. in diameter. Wood light, very strong and hard, coarse grained, and compact. Specific gravity 0.4942 Percentage of ash residue 0.26 Approximate relative fuel value 49-29 Coefficient of elasticity in kilograms on millimeters . . . 1 194. Ultimate transverse strength in kilograms 441. Ultimate resistance to longitudinal crushing in kilograms 8142. Resistance to indentation to 1.27 mm. in kilograms . . . 1950. (Sargent) The coast ranges of California, reaching its greatest development in Men- docino County. Rare and local, in cold peat bogs or barren, sandy gravel below 2000 feet elevation (Sargent). ' The distinction between these two forms of cells is not very clear in this species and is best expressed by the terms " thicker " and " thinner " as applicable to elements which are not very different, or which merge by gradual transitions. PINUS 3^, 37. P. intignit, Douglas Moiittrty Pine Transverse. Growth rings thick, often double. Summer wood rather open the transition from the spring wood very gradual ; the tracheids very unequal in more or less irregular rows, often strongly compressed radi- ally, bpnng tracheids hexagonal, very unequal in somewhat regular rows, the walls medium. Resin passages scattering, numerous, rather large ; the epithelium in 1-3 rows of very large, round, but variable and rather thin-walled, resinous cells. Medullary rays very prominent, broad I cell wide, not very numerous, distant 2-12, more rarely 21. rows of tracheids. Jiadial.Ka.ys resinous, the resin localized, granular, more rarely massive or m the cell wall ; the ray tracheids sparingly reticulated and sparinjfly predominant, when interspersed, very low and unequal. Ray cells of two kinds: (i) cells usually low and prominent, especially in the low rays ; the terminal walls often thick and coarsely pitted ; the upper and lower walls very variable, in the low rays thick and coarsely pUted, in the higher rays thin and barely pitted so as to approach cells of the second order ; the lateral walls with variou.sly oval or lenticular pits 1-2, rarely 6, chiefly 2, per tracheid ; (2) cells straight or variou.sly fusiform ; the terminal, upper, and lower walls very thin, commonly much broken out ; the lateral walls with broadly oval or variously len- ticular pits, 1-3 per tracheid, in the summer wood reduced to much- prolonged shts. Bordered pits in 1 row, sometimes in pairs, elliptical Pits on the tangential walls of the summer wood wholly wanting Tangential. Fusiform rays somewhat abundant, medium, rather narrow, the terminals acute or somewhat prolonged, chiefly composed of small tra- cheids ; the cells of the inflated portion chiefly thin-walled and usi^ally much broken out, but dark and resinous. Ordinarj- rays medium, rather broad, composed of thicker- and thinner-walled cells and presenting four principal aspects: (!) low rays composed of thick-walled parenchyma and tracheids, distinctly fusiform; (2) i-seriate rays composed of sev- eral cells of thick-walled parenchyma and tracheids, usually nonresinous ; (3) i-seriate rays composed of terminal tracheids, t' i'ck-walled and thin-walled parenchyma, usually much broken out through the central region, more or less resinous ; and (4) the highest rays showing inter- spersed, narrow tracheids with strong, local contractions. A tree 24-30 m. high, with a trunk upwards of .90 in diameter. Wood light, soft, not strong, brittle, close grained, and compact. Specific gravity o.... Percentage of ash residue 030 Approximate relative fuel value 45/K. Coefficient of ela.sticity in kilograms on miliimeters . . . 97a Ultimate transverse strength in kilograms 316. Ultimate resistance to longitudinal crushing in kilograms 6680! Resistance to indentation to 1.27 mm. in kilograms . . . 1687. (Sargent) Rare and local, on sandy soil in proximity to the seacoast, California (Sargent). I ''i 1.1 I i 342 ANATOMY OF THE GYMNOSPERMS I ; 1 M. P. SaWntoiu, Douglas Diggtr Pint. Bull Pin* Transverse. Growth rings thick, variable, often double. Summer wood variable, upwards of one fourth to one half the spring wood, from which the transition is somewhat abrupt, dense, or again rather open ; the tracheids very unequal, chiefly in irregular rows, the larger ones often much compressed. Spring tracheids rather large, squarish-hexagonal, uniform in regular rows, the walls thickish. Kesin passages medium, not very numerous, chiefly in the summer wood ; the epithelium of 2 or more rows of large, irregularly flattened and very thin-walled, somewhat resinous cells, often forming an irregular and somewhat extended tract. Medullary rays prominent, somewhat resinous, broad, i cell wide, dis- tant 2-10 rows of tracheids. Radial. Rays sparingly resinous ; the tracheids low but very variable, mar- ginal, predominant and sparingly interspersed, often composing the entire structure of low rays, strongly dentate and .somewhat reticulate in the summer wood. Ray cells of two kinds : ( i ) cells rather numerous, chiefly in low rays ; the upper and lower walls thick, strongly but irreR- ularly pitted ; the lateral walls with prominent, round and bordered, or simple and lenticular pits, 2-5, chiefly 4, per tracheid ; (2) cells rather low and variable, not conspicuously fusiform ; the terminal, upper, and lower walls very thin and entire ; the lateral walls with variously lentic- ular pits without an obvious border, 2-4, chiefly .:, per tracheid, becoming reduced to 1 in the summer wood. Bordered pits conspicuously in 1-2 rows,numerous, elliptical, becoming smaller and round toward the summer wood. Pits on the tangential walls of the summer wood wholly wanting. Tangential. Fusiform rays rather numerous, narrow ; the terminals acute or prolonged linear, chiefly composed of tracheids ; the cells of the inflated portion large and very thin-walled, often much broken out. Ordinary rays chiefly low, not very numerous, ronresinous, broad, the tracheids chiefly terminal and much narrower, rarely interspersed, pre- senting four principal aspects: (i) thin-walled parenchyma with termi- nal and interspersed tracheids ; (2) i-seriatc rays with a few terminal, thick-walled tracheids, but chiefly composed of large and very thin-walled parenchyma cells ; (3) thin-walled parenchyma with terminal tracheids and interspersed, thick-walled parenchyma ; and (4) i -seriate rays com- posed of tracheids and thick-walled parenchyma. A largr; tree 24-30 m. high, with a trunk upwards of 1.20 m. in diameter. Wood light,soft,not strong, brittle and very coarse grained,compact,not durable. Specific gravity 0.4840 Percentage of ash residue 0.40 Approximate relative fuel value 48.18 Coefficient of elasticity in kilograms on millimeters .... 585. Ultimate transverse strength in kilograms 333. Ultimate resistance to longitudinal crushing in kilograms 5387. Resistance . < indentation to 1.27 mm. in kilograms . . 2202. (Sar^, Ver)- common i-i 'he foothills region ; Coast Range and western slope of the Sierra Nevadas below 4000 feet elevation, California (Sargent). PINUS 343 S9. P. tada, Linn. /<«»A>//> P,Ht. Old /•/./,/ I'ini ^'"T,f!!^f?™T''M"*' l?'"?**- ^"""""' ^-^ "P*" "' Hometimcs rather dense, often double and often equal t.. the sprinj; wo.k1, from which the Uansition ,s abrupt ; the tracheids large, stronglv une.i^al but in rather regular rows. Spring tracheids large, s(,uari.sh, the walls thin. Kesin passages numerous, chiefly in the .summer wood, very large ; the euithe- lium composed of very thin-walled, sometimes resinous cells, chiefly in I row and strongly compressed upon the face of the tracheid structure, more rarely becoming 2-rowed in part and forming an eccentric tract of limited extent. Medullary rays rather prominent, broad, i cell wide, distant 2-8 rows of tracheids. . , .; wiuc. Radial. Rays nonresinous ; the tracheids sometimes predominant in the higher rays, but often interspersed, low and unequal throughout, .sparingly, rarely strong;ly reticulated. Ray cells of two kinds: (1) ceils rare and occurrmgonly (?) in the low rays, where they are conterminous with the tracheids ; the terminal walls thin and entire ; the upper and lower walls thick and strongly but incompletely pitted ; the lateral walls with round or oval pits, upwards of 6 per tracheid; (2) cells variously fusiform, often straight ; the terminal, upper, and lower walls verj- thin and com- inonly much broken out ; the lateral walls with variable, oval, or lentic ular pite, 1-6, chiefly 2-4, per tracheid, in the summer wood commonly reduced to i. Bordered pits in i or 2 rows or often 1 row or pairs, elliptical. Pits on the tangential walls of the summer wood wholly wanting. The tracheids of the summer wood sometimes exhibit a dis- tinct tendency toward the formation of spirals. Tangential. Fusifonn rays rather high and narrow, the terminals acute or prolonged and finally wholly composed of .small tracheids ; the cells of the inflated portion commonly wanting. Ordinarv- rays medium and presenting two principal a.spects: (.) higher rays composed of thin- walled parenchyma cells chiefly broken out, with very .small, terminal, and interspersed tracheids, the latter causing local contractions; and (2) lower rays of thin-walled parenchyma much broken out, rarely showing a thick-walled parench>-ma cell, and small, terminal tracheids. A large tree 24-46 m. high, with a trunk upwards of 1.50 m. in diameter. Wood light, not strong, brittle and very coarse grained, not durable. Specific gravity Percentage of ash residue o 26 Approximate relative fuel value ......... i^.z-j Coefiicient of elasticity in kilograms on millimeters '. '. 11 28 Ultimate transverse strength in kilograms 377I Ultimate resistance to longitudinal crushing in kilograms 6834. Resistance to indentation to 1.27 mm. in kilograms . 171Q (Sargent) ' ^' Low, wet clay or sandy soil ; southern Delaware to Tampa Bay, Florida, generally near the coast ; westward through the Gulf States to the valley of the Colorado River, Texas, and northward through southern Arkansas to the valley of the Arkansas River (Sargent). . \ [I' ' I . :i, 1 ■ I 344 ANATOMY OK THK (;YMN0SPERMS 40. P. pdttttria, Miller Leng-I^mtii Pint. Southtrn Pint. Ytlbw P'h4 Transverse. Growth rings thin, very variable. Summer wood dense, often very thin, the transition from the spring wood very abrupt ; the tracheids very uniform in regular rows. Spring tracheids squarish, rather uniform, in regular rows, often radially elongated, the wallr. rather thick. Kesin passages numerous and large, chiefly in the summer wood ; the epithe- lium composed of large, rounded, often resinous cells in i row, fre- quently becoming several-rowed in part and forming more or less extensive and strongly eccentric tracts about the canal. Medullary rays very prominent, broad, i cell wide, distant 2-10, more rarely 15, rows of tracheids. Kadial. Kavs sparingly resinous throughout : the ray tracheids often inter- spersed, commonly predomiiiant, very strongly reticulated throtghout. Kay cells of two kinds : H) rathi-r few but prominent and conterminous with tracheids into which they merge ; the terminal walls thin and not pitted ; the upper and lower walls somewhat strongly but unequally thickened and pitted ; the lateral walls with broadly and variously len- ticular or round pits, 2-5 per tracheid ; and (2) very long-fusiform cells ; the terminal, upper, and lower walls very thin and usually much broken out ; the lateral walls with very variable, lentictilar, or oval, sometimes ver)- large, pits, 2-6, chiefly about 4, per tracheid, in the summer wood reduced to I. Bordered pits conspicuously in 1-2 rows, elliptical. Pits on the tangential walls of the summer wood wholly wanting. Tangential. Fusiform rays not numerous, often very high, acute, the linear terminals much prolonged with terminal or interspersed tracheids, but with the structure very commonly wanting except at the extremities ; the low, inflated portion usually showing only a remnant of v -ry thin- walled, delicate tissue. Ordinary rays medium, rather numerous, broad, presenting three principal aspects : ( 1 ) low rays with few, thin-walled parenchyma cells much broken out, and terminal tracheids of very vari- able size ; (2) higher rays of several large, thin-walled parench)rma cells much broken out, and narrow, oval to oblong, terminal tracheids, rarely with interspersed thick-walled parenchyma; and (3) the highest ray.s composed of a few large, thin-walled parenchyma cells, with small, ter- minal, and narrow, often high and interspersed tracheids. A tree of the greatest economic value 18-29 "*■ l^'g^i ^>th a trunk upwards of 1.20 m. in diameter. Wood heavy, exceedingly hard, very strong and tough, coarse grained, com- pact, and durable. Specific gravity 0.6999 Percentage of ash residue 0.25 Approximate relative fuel value 69.82 Coefficient of elasticity in kilograms on millimeters . . . 1,488. Ultimate transverse strength in kilograms 490. Ultimate resistance to longitudinal cru.shing in kilograms 10,074. Resistance to indentation to 1.27 mm. in kilograms . . . 2,508. (Sargent ) PINU55 ,^- 345 bw, wet «,il. Southeastern Virginia to Tampa Hay. Florida- nentla < Kiver inlexaM; rarely more than 150 miles from the coast (Sargent). 41. P. cabentU, Griseb. S/atA Pint. Swamp Pint ^''""ZZ*. ^.^"V' "*"«!• '■*"»''''• *'^""""«' ""^ variable, deni« or ooen the transition from the spring wood usually vtry abruo th^.r/.-K'TJ^' passages numerous, large, chiefly in the summer wood : the epithelium In 1-2, rarely 3, rows of rather thin-walled. usually much flattened^ resinous eels. Medullary rays prominent, very boad,, cell wWe" fiadial Kzy* sparingly resinous ; the ray tracheids rather hiuh oredominan. ZIaVZ 'T «>:«^here very strongly reticulated Ra;'^dU o two kinds: (i> short-fusiform ceils equal to about 4 spring tracheid,- Z terminal walls thin and entire, locally thickened or'^ily pitted ^ he tZ^' *"'*^'-*" T*' ' "^'" '""^ much broken down, bu? more'^^omrn'only thicker and irregularly pitted, these two forms gradually merginKS^fi Zlu! T-I'^'^^ ?"P"';'^''' •*"""^"'"«='' conteLinous wiTh a^'nd m^ 'fng ihi fl v!!**" ' ""*= ''"="' *»"^ *"*> ^"""We, chiefly lenticular pTtsT 6 K- '*^l!' I"-*' P^"" 'i;""*"^''^' '" •»'* *""""" w«"d reduced to Ht or becoming obsolete. Bordered pits in 1-2 rows, numerous, elliptical in the summer wood quickly reduced and finally obscure rwhXwan^in/ icu^ o rn rn °™ ;,»>''';'">'" numerous, high, and narrow, the temiinals acute or prolonged and composed of very large, broadly oval paren- Uorcoml's^d"'* ?7. '■■^^/r '"=" '^-ch'eidsf the short inflated ^^r- OrSinai^^^r t *'""-*='"'^'l parenchyma cells much broken ^t. oval rnm^ln rj'""-"*'"'*' ''™="^' '"'='"""'• »»^« ""» ^^^iefly broadly oval, composed of dominant parenchyma cells with chiefly terminal sparingly interspersed, often high, and narrow tracheids. ' A tree 24-30 m. high, with a trunk upwards of .90 m. in diameter ^ durabl'e"'"'''"^'^ '"'"'' ^''^' ''™"^' '''"^''' '"^''^ «''''"''*• '^'""P**^'- Specific gravity . . . Percentage of ash residue '. \ °olf°'^ Approximate relative fuel value ,°b Coefficient of elasticity in kilograms on millimeters '. ' '. ^ 577 ^ Ultimate transverse strength in kilograms ... 5^0' Ultimate resistance to longitudinal crushing in kilograms ' 10,626' Kesistance to indentation to 1.27 mm. in kilograms . 2 985 . 1 I-l •,^ St I 346 ANATOMY OF THE CAMNOSHERMS South Carolina and xnuthward near the coaitt tu the Kloriiia Key* wculward along the (iulf toasit to the I'carl River, L<>ul»iana, not nunc than o or (m mileii inland; alio in the Wcitt Indie* (Sargent) ; Uahanuw and IhIc of Pine* (Shaw). B. HITYOXYLON (Finoxylon) /■iuti/ Sptdn Only 49. P. dMOtOlM, Knowlton " Tranrvtrst. Annual rings broad and very distinct, even to the oaked eye, being 2-45 ram. in width. Distinction l>etween the xpring and autumn wood very plain, the former appearing as broad, white bands, and the latter as denae black bandit of varying width. Under the mit nj. kcope the line of demarcation between fall and spring wood Ik obser\ed to be very sharp indeed. The fall wtiod consist.^ of thick-walled cells of an elliptical or oblong outline, rather loosely placed. The aucceeding spring wood i» compoHcd of very large cells with relati' ely thin walK. The medullary rays are long and quite thick-walled. There are no resin cells in the wood. The re^-in pa.ssage8 are present and (juite numerous. They do not seem to be cunfined to any particular portion of the ring, but are scattered, being perhaps m<)»t numerous in the fall wood. They are of relatively large size and lined with thin-walled epithelium. " Radial. The walls of the spring and summer wood have 2 rather irreg- ular rows of large, bordered pits. In rare ca.ses these pits are in a single row. The average size of tlie outer cirtk is .025 mm., that of the inner circle about .015 mm. The crlls ot the ays are rather long, covering the width usually of some 4 or more ceils of the spring wootl. They are rather thick-walled, the walls l)eing .strongly dentate or somewhat irregularly thickened. The ray cells are provided with ui few scattered, bordered pits, usually only I to the width of a spring cell of the wood, although not rarely there are 2 in a similar idth. They are always in 1 row on the ray cell. " Tangential. Medullary rays in a single, uperimposed series, from 1 to rarely 30 cells, the average being from 5 12 cells high. None of the rays in the sections examined are of the fusiform type or contain resin pas.sages. The wood cells are, as far as can be made out, without pits or markings of any kind" (Knowlton). Trunks of medium size ; material silicified. Upper (?) Jurassic near Sturgis, South Dakota (Knowlton). 43. P. Alderaonl, Knowlton " Transverse. The annual rings are very distinct, being plainly discemilile to the naked eye. Some of the broadest rings are fully 9 mm. wide and none less than 6 mm. The demarcation between fall and spring wooa is very pronounced, the cells of the fall wood being small, conipressrd, and thick-walled, while those of the early spng w^iod are very lart;e, and, of course, thin-walled. The cells of the yi-ri.ig and summer w.mhI continue for a width of 5 mm., but little, if .iiy, .minished in si/i-. In I YOXVI.ON 347 I rien ^\w^ hecom* HlJi-htl v MnalWr awl lit. r-walled and imm gradually Bto n, fall «,H .1 ihe n^i„ ,1,h,« ,,re vt , larxc. They arc not found in Ih. umnuf wojxl, I.,.. ,h;i ur irre^iiiarly In the early fall an.d late tall wooci The n.rdullar> r.iVH as ohwrvcd in thi* w, M„n arc stiaji{hi .,nd Hcpara.ad In j « or lo ro». of woo of the Ydlowsionc National I'ark, at Specimen Kidgc, near head -A Crvtal Creek, anr' Yancy Fossil Forest (Knowlton). 44. P. unethystinttin, Kno-vkon " Tramrcrse. Much like V. Aldersoni except that the rings are narrower, xhv cells of the spring and summer woikI are smaller, and the late fall cells have thinner walls. The resin du< ts a-o ■; much the same, being in general only a little smaller A fi: ..•• , i,, the summer wood, but most of them are in the f.ill v^ he » ; are not nearly so numerous as in the last species. Tre> art often separated by as many a.s 25 rows of wood cells. " Kat/ial. The radial section of nearly .ill woods from the Yellowstone National Park is more or less obscure. The one under consideration is no exception to this rule, and it is only alter considerable search that the pite can be determined They are in a single row and are rather small. They are so obscure that it is impossible to make trustworthy measurements. The medullar)- rays, as seen in this section, are com- posed of long, thin-walled ct lis, and, so far as can l>e determined, they are without pits or other markings. " Tangential. This .section shows the structure very plainly. The medullary rays are abundant and always in a single .series, except the large, com- pound ones. The numlier of cells in each ray varies from 2 to 10 or 1 2, the average number being about 6. The compound ravs inclosing the 348 ANATOMY OF THE GYMNOSPERMS I; resin ducts arc rather small, with 3 rows of cells in the middle portion. No markings can lie made nut nn the wood cells in this section " (Knowlton). This species is very closely allied to the preceding, and should perhaps be referred to it. The main j)oints of difference are the following: smaller resin ducts that are occasionally found in the summer wood ; smaller wood cells throughout ; smaller and shorter compound medullary rays ; ordinary rays always in a single series of 2-12 cells (average 6) instead of 2-30 or more (average 12) (Knowlton). This species cannot be separated from the preceding on the basis of the characters given, and it is undoubtedly the same, though recognized here provisionally (I). P. P.). Trunks of small and medium size. Material siliciiied. Tertiary of the Yellowstone National Park at Specimen Ridge, near the head of Crj'stal Creek (Knowlton). 45. P. Columbiana, Penh. Transverse. Growth rings variable though generally very broad in large stems. Spring wood usually predominant, the transition to the summer wood gradual but in the narrower rings more or less abrupt and some- times conspicuously so ; the tracheids large, thick-walled and often con- spicuously so, definitely rounded, often radially oval, chiefly uniform, more or less eoual, in regular radial rows. Summer wood conspicuous, dense, and ofteii rather thin. The structure as a whole is that of a rather dense wood of medium hardne.ss. Medullary rays prominent, not very numerous, resinous, and distant upwards of 9 or more rarely 1 5 rows of tracheids. Resin pa.ssages conspicuous, rather large, and scatterin}; throughout the growth ring, the parenchyma cells large, thin-walled, and in 2 rows, or forming large and irregular tracts upwards of 6-9 tracheids wide, resinous ; thyloses not obvious. Radial. Medullary rays resinous ; the tracheids rather numerous, marginal and intersijersed, not obviou.sly predominant, very variable and often as high as or higher than, long, sparingly dentate ; the parenchyma cells all of one kind and rather thin-walled, straight, and equal to about 4 wood tracheids; the upper and lower wails strongly (?) pitted; the terminal walls straight or diagonal and apparently not pitted; the lateral walls with simple, round or lenticular pits of medium size, 2-4, chiefly 2, per tracheid. Bordered pits on the tangential walls of the summer tracheids small and not numerous ; those of the radial walls rather large, round, or oval in I compact row, and generally numerous. Tangential. Fusiform rays rather numerous, short, the broad central tract with thin-walled parenchyma chiefly broken out, the unequal terminals composed of broad, oval cells chiefly in 1 row. Ordinary rays low i.> medium, i-seriate, not materially contracted by the interspersed tra- cheids; the parenchyma cells somewhat unequal and variable fnmi oblong to oval or broad and round. Calcified fragments of stems and branches, and also cones in the Tertiary of Kettle River, near Midway, British Columbia. 1'irvoxvi.oN 46. p. Petli, Knowlton 349 ^Z".- .J" I^^T "''*'*'' "^"^ '»'« ^^' »"d Mrly sprinK wood The contrast m he thickness of the cells makes a very clearKS rin/ yCTf n^ ^°*"' T'* ""7 broad, being in some cases Mly ,o mm" ">pJi/ 7/'""»'-y.">« ^''"'^ in this section also as long, slen, " ce Is -RaAal. Ihe specimens are in a fine state of preserva ion The cells of the spnng and summer wood are very broad and ma ked «ith% siLli *enes of large, scattered, bordered pi'ts. The meduHa^ ray are prom " Tangential. The medullary rays are arranged in a single series of from - themidTnf ' 2o superim,x>sed cells.* The resin^tubeToccurrir i„" the midst of a medullary ray are quite numerous. There are no recoJ^ jKnowitCLr"" "'" " "" ''"^•="'"' "^"'^ ofThr;;^"S' Material silicified. Miocene of the upper Gallatin Basin, Montana (Knowlton). 47. P. chasense, Penh. 7V««.«/^r.r'"'*''= (') '••''^^''««'= ray.s, the cells oblong 2, « broad often 2-ser.ate in part ; and (2) fusiform ray.s, the terminals li^ei^ and of the structure of the .-.seriate rays; the centra! ' Vctv'er broad nearly round , the cells large, thin-walled, irregular. anS inc?osS a small, central resin passage with large epithelium cells. ^ Material silicified. Specimens represented by small fragments of stem Klsas^frosrerr™^'"^" (^^™'^"> "' ^'"°" ^^-•'> ^^^^ bounty. \*. 48. P. 8Utenene«, Jeff, and Chrys. rransi>erse. Growth rings vari.ible, chiefly narrow but usually well defined • summer wood very vari.-il.Ie. of ,h/ narrower rings . - s! 1 uf of The" ^v!. .'■,.""*^'.'"u."y '"'^heids thick and constituting upwards of two Ib'rtt the"'tS''"'="' 'T""°" ^'°"' thesprin,^wLi ^mewhat abrupt, the broader growth rings sometimes showing 2 zones of summer wood. Trachcids round-hexagonal or rectangular rather M 350 ANATOMY OF THE GYMNOSPERMS uniform but conspicuously unequal, disposed in unequal and some- what irregular rows; those of the spring wood thin-walled, about 32 X 39 ^ those of the summer wood rather thin-walled, about 19 x 29/i. Medullary rays very resinous, broad, 1 cell wide, and distant about 2-8 rows of tracheids. Specialized resin cells wholly wanting. Resin passages numerous, large, chiefly in the spring wood and filled with prominent, resinous thyloses, the epithelium 1-2 cells thick, and not extended into parenchymatous tracts. Radial. Bordered pits very numerous in 1 row, rarely contiguous ; round, more rarely oval, and about I7S M> the round orifice about 7 /*; in the summer wood somewhat reduced. Pits on the tangential walls of the summer wood prominent, large, somewhat numerous. Medullary rays very resinous ; ray tracheids wholly wantk:ig ; parenchyma cells all of one kind, more or less contracted at the ends, very /ariable but generally equal to about 3-5 spring tracheids ; the upper and tower walls strongly and rather frequently pitted ; the terminal walls coarsely pitted or locally thickened ; the lateral walls with rather small, oval pits, chiefly 1 per tracheid throughout, or in the marginal cells and low rays 2 per tracheid. Tangential. Fusiform rays numerous, medium ; the cells thick-walled ; the frentral tract broad and occupied by i large resin canal filled with thyloses; the terminals chiefly short or rarely prolonged with 1-2 seriate cells. Ordinary rays very variable but chiefly low to medium, sometimes more or less 2-ser'ate in part ; very numerous ; the cells broad but variable and round, oval or squarish, chiefly equal ; in the low rays commonly becoming oblong. The middle Cretaceous at Kreischerville, Staten Island, form of lignite (Jeffrey). Material in the 49. • • P. adtuatense, Jeff, and Chrys. Transverse. Growth rings rather broad but thin, the limits obscured by displacement of structure ; summer wood chiefly broad, the transition from the spring wood apparently gradual. Tracheids all rather thin- walled, those of the spring wood about 26.7 x 44.5 ^. Medullary rays numerous, prominent, resinous, broad, 1 cell wide and distant about 2-5 rows of tracheids. Kesin canals rather numerous, chiefly in the summer wood and central to broad tracts of parenchyma ; devoid of thyloses, rather small, regularly oval or round, the epithelium composed of a single layer of rather small, rounded, and somewhat thick-wallcd cells. Wood parenchyma resinous, the cells large, thin-walled ; forminj,' extensive and prominent tracts about the resin canals often 427 x 570 /i broad. Radial. Bordered pits in 1 row, somewhat distant and not numerous ; round, about 24.6 ^ broad, the lenticular orifice showing a cross ; ndt much reduced in the summer wood. Pits on the tangential walls of the summer tracheids not determinable, apparently wanting. Medul lary rays resinous ; ray tracheids apparently wanting ; the parenchym.i cells all of one kind, not contracted at the ends, equal to about 5- ri wood tracheids ; the upper and lower walls rather thick, distantly and PITYOXYLEN 351 coarsely pitted ; the tenninal walls rather thin and locally thickened ■ the lateral walls with round, bordered pits about 1 1.5 /i broad, chiefly I, or sometimes 2, per tracheid, the orifice lenticular, diagonal. Wood parenchyma resinous ; the cells cylindrical, 2-several times longer than broad, the radial walls with rather small pits. Tangential. Ordinary rays resinous, numerous, variable, low to high, 1-2 senate, or sometimes 3-seriate, and approximating to the fusiform type through various gradations, but always devoid of resin canals • the usually large cells very unequal and very variable, ranging from oblong to oval, round or transversely oval, the strong inequality and variability giving a marked irregularity of form to the ray as a whole. Fusiform lays rather numerous, low to high, the central tract occupied by I rather small resin canal devoid of thyloses, but with small and thick-walled epithelium cells ; the terminals short or sometimes un- equally prolonged to considerable length. Wood parenchyma resinous, the short-cylindrical cells with thin walls and bearing pits on all their walls. Rudimentary spirals may be seen in the tertiary layer of many of the tracheid walls. ■' Cretaceous (?) of Third Cliff, Scituate, Massachusetts, form of lignite (Bowman). Material in the B r lit 11 11 I ■%, If 'W^' APPENDIX A DATA FOR TABLE OF ANATOMICAL CHARACTERS. IN IDENTICAL SERIES I. 2. 3- 4- S- 6. 7. Spiral tracheids. Bordered pits in 1-3 rows. Bordered pits in 1-2 rows. Bordered pits in i row. Pits on the tangential walls of the summer wood. lateral walls of the ray cells with bordered pits. I -seriate rays. 8. Terminal walls of the ray cells thin and entire. 9. Resin cells. 10. Terminal walls of the ray cells locally thickened. 1 1. Terminal walls of the ray cells strongly pitted. 12. Ray tracheids. 13. Resin passages. 14. Fusiform rays. 15. Thy loses in the resin passages. 16. I.ateral walls of the ray cells with simple pits. 17. Ray cells of two kinds. Resin cells scattering. R';sin cells zonate. Resin cells grouped. Resin cells on the outer face of the summer wood. Ray tracheids marginal. Ray tracheids interspersed. Ray tracheids dentate. A. Number of species. B. Percentage value of genus. .353 It 354 o u o < < o o < 5 s < < a o u s H b O cfl U H O < ft, < X u < 9 ANATOMY OF THE (iYMNOSPERMS e -- ^ J n '^^ D^* * K^JHI^ ^ \ < Mf>) -««> ♦ w«--»f«> M 0> - « X t»> X X « ^x X xj X X x2 X - XXX 33 xxxxx XXX r<. - >< * ? « 1 X X o 5 XXX 0^ XXXXXXXXXXXXXXXX 00 XXXXXXXXXXXXXXXXXXXXXXXXXl 1 1 l>. xxxxxxxxxxxxx^xxxxxxxxxxxxxx \o xxxxxxxxxxxxxxxxxxxxxxxxxxxx \f\ xl t Ixixixxxxxxxxxxxxxxxxxxxx t X ^'<^>ii^.iii^.iijLii<;x X X X x"x7irx^Vx"ir^ ^.^_^>^,>^ xxxxxxxxxx X X X X x~>7^i^ X X X X X X X xxxxxlllillllll lilllllllllll I I I I I I I I I I I I I lilllllllllll I I I I I I I I I I I I I I I lilllllllllll I I I I I I I I I I I I I I I lilllllllllll Jfc? 1 Q z U Oh < X X X X X X X ^^^^ XX xxxxxxxxxxxxx xxxxxxxxxxx xxxx xxxxxxxxxxxxx xxxxxxxxxxxxxxx xxxxxxxxxxxxx xxxxxxxxxxx XXXXXXXXX I X X X X ~ I X X X X X X X X X X ;5x X X X X XXX TiT xxxx 11 I I I I I I I I I x^ I I I X i, I I I I 53 I 3^ I I as X X X X X I I I I I I I I I lilllllllllll lilllllllllll XXXXXXXXXXXXX i_L X X I I I I ^^ X X X X X X X XXXXXXXXXXXXX XXXXXXXXXXX xx'x^xxxxxx ^xxxxxx^ xxxx xxxxxxllllill ^xxx xxxxxxxxxxxxx xxxx xxxxxx X X X X X I X X I I I u .3 n v u gOTS C 3 ■- X - « 6 O O c< p.-; .2 S a.' 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X < 0 '•J 1 1 ro 9^ nfi r»l — ^ ly^sO 0 oOCO*n"^»'^OP» •• ^ pi PI PI PO PI P^ pi -■ PI PI PI ~ P*^ ■• ™ "■ •" P* ** 1 s r^ r^ ^ r^vC O 00 to PI 00 t^ "^ »^0 00 PI PI PI PI PI r^oo 00 u^ i>> ■<»• r^ -^f t^vo «^p*^iri^^t^^'4'tP* -^-^ 1 in ri fi fi n X X PI pi PI pi pi p* PI pi •- PI PI pi PI PI pi PO PI pi pi X S < ae H (b D n ■0 1 "1 CTv 5- CvO pi pi pi 00 0 PO \0 0 0 C^C^O rs.Pi r^-i'0\- — 2C too C^ pi y) ^ — C>nO p^ pi to r^oo CJ^r^ — OvO pi — O C>-T pi -4 "^ « pi pi PI •- pi — « PI ■- pi "■* PI ci pi " w — « ■- i Summer Wood T. R. X 00 X r* — PI PI XXX 0> r^ "^ PI PI PI 0 PI X C\ PI pi d 10 PI p^O -■\0 r.OPi OM^»or^c»Pl CNf^ P|.«>«P|mP|P|»*m»P|»-h — »»mmPI XXXXXXXXXXXXXXXXXXX pi-n-ooo PI pn—o^ PI o>vo ■■ r^ 0 ^o 't-^o \o ro PI PO PO PP^ PO rn PI PI PO PI PI PI pi p^ pi n pO 'T ■8 be X X 3, P^O VO •^ "^ -r XXX - 00 PO r^N PO to X 1 OS to to OsdoOvOvO -»-t^-»-POi^i^PO'*-tto- lOovO toPOPI POPO^-TPI ■^PnrOP'^PI POPO-I-PI to-^ XXXXXXXXXXXXXXXXXXX to PO to to to to todvd « Tfrioo top^pi — M ■^j'Pi CsvO -^ 0 0 POPI rOPOPOPOPPJPI PPlPOP^P^iPI PPJPI PI PI ^-* 1 g c V a 1 ■ftb 3 a a 3 S 3 1 macrocarpa J^arix occidentalis americana . Is leptolepis . Picea IJreweriana rubra . . alba . . . Engelmaniii jesoensis . Kjlita . . )icolor . . pungens . nigra . . sitchensis . rinus Parryana . cembroides monophylla Balfouriana aristata edulis . . I^mbertiana monticola . APPENDIX B 361 0 00 E u "o 31 n >^ ro N N^ M M H N^ ro S. 5 s, ^ '^ •" " — - f i fi »■ » ^^ ro N M M N f4 M f ; «->4 4vo 4 ti >>i . . . 00 30 f 1 00 00 M ^ 1^ r^vO ^ ^ tA. ^ ^ d 2 Jf H^ r^ .7ff!?^"» 5;^£'^JC3>^?,>?K . » ri _ _ M ri J fi N pi -; pj ^ „• ^i ^ ^ PI - _ ri ,. 00 VO 1^ P^ PI M i#i O'jo r^ — o O 0^ « fi p. N P. P. N ^ ;; ;; fr«3 ;f^<> j>- ^^w o - jj>jpj>w ^- onvo p-. r^ c> ^o u-i 00 "^ioOnOvD M ri XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX r\0 O ri ^ ^ ^ f^ ^ „ j^^x M .*K .*. .- o ;^^«?,?,.H ° >- c s .a -^ IE 1*1 2 ppi-r^sg S S '5 5i y 3 5 ^ S M Q. « Ti-C SCO ST1,« >> CC«i^ !ir\ ■s = S 3 J) kmBiOu'Cnn ^S 2 .a as S 0 = Hi rt Ir -^ Fp.S •3 = ^ B-as ssh^s §o2H-g^aa S..S iJI «! 1 ft*--" LITERATURE Anderson, A. P. (1) Ueber abnorme Bildung von Harzbehaltem. MUnchen, 1896. (>) Comparative Anatomy of the Normal and Diseased Organs of Abies balsamea affected with vEcidium elatinum. Bot. Gaz., XXIV, 30^3441 1897 (Plates XIV- XV). BoULGER, G. S. (79) Wood: a Manual of the Natural History and Industrial Applications of the Timbers of Commerce. London, 1902. BovEY, H. T. (8) Theory of Structures and Strength of Materials, pp. 213, 215. (4) Presidential Address. Trans. R. S. (Canada), II, iii, 3-24, 1896. (6) Results of Experiments on ths Strength of White Pine, Red Pine, Hemlock, and Spruce. Trans. Can. Soc. C. E., XII, 207, 1S97. (6) Results of Tests of White Pine of Large Scantlings. Trans. Can. Soc. C. E., VII, 13s, 1893. (7) The Strength of Canadian Douglas Fir, Red Pine, White Pine, and Spruce. Trans. Can. Soc. C. E., IX, 69, 1895. Brixton, N. L., and Brown, A. (•) Illustrated Flora of the Northern United States and Canada. New York, 1896. Campbell, D. H. (9) Text-Book of Botany, p. 335. Constable, Howard. (10) Wood Preservation. U. S. Dept. of Agriculture, Forestry Div., Bull. ' -887. Coulter, J. M. (11) The Gymnospen.is and the Seed Habit. Bot. Gaz., XXVI, 153-168, 1898. Coulter, J. M., and Chamberlain, C. J. (19) Morphology of the Spermato. phytes. New York, 1901. De Barv, a. (18) Comparative Anatomy of the Phanerogams and Ferns. Oxford, 1887. (88) Comparative Morphology and Biology of the Fungi, Mycetozoa, and Bacteria. Oxford, 1887. Dudley, P. H. (14) Structure of Certain Timber Ties ; Behavior and Causes of their Decay in the Roadbed. U. S. Dept. of Agriculture, Forestry Div., Bull. I, 1887. •^ichler, a. E. (16) Naturlichen Pflanzenfamilien, II, 6 et seq. Engler, a. (16) Naturlichen Pflanzenfamilien, II, 24 tt seq. Engler, a., and Prantl, K. (17) Naturlichen Pflanzenfamilien, II, 7-127. Essner, B. (18) Diagnosticher Werth der Anzahl und Hohe der Markstrahlen bei den Coniferen. Bot. Centralbl., XII, 407, 1882. Fischer, H. (19) Ein Beitrag zur vergleichenden Anatomie des Markstrahl- gewebes und der Jahrkichen Zuwachszonen im Hblzkorper von Stamm, V ;1 und Aesten bei Pinus abies, L. Flora, LXVIII, 1885. 362 hit^Miriaft- LITERATURE 363 ^:|) . of Agriculture, Forestry K:ad. IIf.nrv. (90) Wood Pre-ervatior,. U. S. 1, L>IV., Hull. I, pp. yj-^S, ,887. GiiPPF-RT. n. R. (M) Kossilen Coniferen. Leiden, ,850 ARTIG,r.EoKoI.,„w,r.. (81) I.el,rbuch fur ForMc. S.ut.gart, 1877 hT^:: TnlTinT^'': "" '";:!!''" N^'de.wa.dbaume. ^e^L ^^885. HolucVa J^^^ der Ho.zp«a„.en. Berlin'. .878. , *im jtKhREY, li. c. (17) Affinities of Certain Cretaceous Plant Remains commonly referred to the Genera Dammara and Brachyrhyllum Amer. Nat.. XL, No. 471, pp. 189-2.5. .906 (Plates I-V). "'"^.liles''pa?t*l Th" ^""'T'" """"""^ ""'• ''''y'°8''"y °^ 'he Conif. — (»»T A Fo« I ^ r' ''\^"°'*- ^""- "°'"°" «°- ^'="- «''*'•. ■903. 2,- f 1 '*'*'^ '*''^''''''- ^°'- ^''^- XXXVHI, JEKFREVEC andCHRvsLKK.M.A. (M) On Cretaceous Pityoxyla. Bot. Gaz XLH, No. I. pp. ,-14, ,906 (Plates I-II). ' Knowlton F H. (S6) New Species of Fossil Wood (Araucarioxylon arizonicum) from Arizona and New Mexico. Proc. U. S. Nat. Mus., XI. ,888 ^ — (27) Descnption of Two New Species of Fossil Coniferous Woods from ««. . 'v ^°"'^"*- ^"^- "• ^- ^="- ^'"*- >^I. S-8. .888. ~ Descrim"r^°p''',*'«™" ^■■-"rioxylon of Kraus, with Compiled De captions and Partial Synonomy of the Species. Proc. U. S. Nat. Mus Ail. 601-617, 1890. ~ ''xiiLX:8V.8r """ ''"'" '"'^' '"'''"'• "'""• "■ '• ^^»- ^-■• ~^'sir:.tl..T6:l^^^^ ''«"^"' °^ "-^ ''°'°-- ^°""--- -■ - Oeol. — (81) Descripaon of a Supposed New Species of Fossil Wood from Montana BuU. Torr. Bot. Club, XXIII, 250-251, 1896. — (88) Description of Fossil Wood and Lignites from Arkansas. Ann. Kept Geol. Surv. of Arkansas, II, 249-266, 1889 ^ (88) Description of Known Fossil Plants from the Laramie of the Yellow- st^one National Park. U. S. Geol. Surv., Monogr. XXXII, Part II, eli-Z, ~~ ^ U^ SC^Tr" °i"!r ^'■^'='"°"^ ^"'l Tertiary Plants of North America, u. i>. tieol. Surv., Bull. 152. 1S98 Macoun,^Johx. (88) Catalogue of Canadian Plants. Exogens. Geol. Surv. Can.. -— (86) Kept. Geol. Sur^-. Can., p. 2,,. ,875-1876. SSX, xx''!'.."-" °" "■• "'"■' - '■— •"-' --'«-- if!! V"^ Cypresses of Monterey. Garden and Forest, VII. 298 -—(88) A General View of the Genus Pinus. Jn'l Linn. Soc. XXXV c6o-6co MuLLER. N. J. C. (40) Atlas der Holzstructur. Halle, ,888 -— (41) Botanische Untersuchungen. Heidelburg, 187- Murray, A. (48) Edinburgh New Phil. Jn'I, .n. s., I. ill 364 ANATOMY OF THE GYMNOSPERMS I- 6 NoRiii.iNr.FR, H. (48) Die Technischen Eigenschaften der lliil/er. Stuttgart, i.Sf)0. rKNiiAi.i.<)W, I). P. (44) Taxacex and Coniferac. Trans. R. S. (Canada), II, iv, 33-56, i8g6. (48) North American Species of Dadoxylon. Trans. R. S. (Canada), VI, iv, 51-79, 1900. (46) Notes on Tertiary Plants. Trans. R. S. (Canada), IX, iv, 33-95, 1903- (47) Contributions to the Pleistocene Flora of Canada. Trans. R. S. (Canada), II, iv, 59-77. 1896. (48) Canadian Pleistocene Fauna and Flora. B. A. A. S., pp. 525-529. Bristol, i8<)8; pp. 7-12, Bradford, 1900. (49) The Pleistocene Flora of Canada. Bull. Geol. Soc. Amer., I, 31 1-334. 1890. (80) Notes on the Cretaceous and Tertiary Plants of Canada. Trans. R. S. (Canada), VIII, iv, 31-91, 1902. (81) Notes on Tertiary Plants from Canada and the United States. Trans. R. S. (Canada), X, iv, 57-76, 1904. (89) Observations upon Some Structural Variations in Certain Canadian Conifera;. Trans. R. S. (Canada), XII, iii, 19-4'. '894. (88) The Relation of Annual Rings to Age. Can. Rec. Sc, I, 162. (84) Some Peculiarities of Plant Growth. Science, III, 354. (88) An Ancient Blaze. Can. Rec. Sc, III, 500. (86) Osmundites skidegaiensis. Trans. R. S. (Canada), VIII, iv, 3-29, 1902. (87) Notes on Nematophyton crassur.i. Proc. U. S. Nat. Mus., XVI, 1893. (88) Notes on Devonian Plants. Trans. R. S. (Canada), VII, iv, 19-30, 1901. (89) The Anatomy of the North American Coniferales. Amer. Nat., XXXVIII, 243-273; 33'-3S9; 523-534; 691-723,1904. (80) Variation of Water in Trees and Shrubs. Amer. Nat., April, 1886; Can. Rec. Sc, II, 105. (88) A Blazing Beach. Science, XXII, 794-796, 1905. Pierce, J. G. (60) Studies on the Coast Redwood. Cal. Acad. Sc, II, 83-106, 1901. P0TON16, H. (61) Lehrbuch der Pflanzenpalaeontologie. Berlin, 1899. Prantl, K. (69) Naturiichen Pflanzenfamilien, II, 33-40. Roth, Fu.ibert. (63) Timber Pines of the Southern United States. U. S. Dept. of Agriculture, Forostry Div., Bull. 13, pp. I33-M3- Russow, E. (64) Zur Kenntniss des Holzes, Insonderheit des Con.ferenholzes. Bot. Centralbl., XIII, 29-40; 60-68; 95-109; 134-144; itJ-173, 1883. Sachs, J. (84) Physiology of Plants. Oxford, 1887. S\Rr.ENT, C. S. (68) Forest Trees of North America. Tenth Census of the United States, IX (the whole volume), 1880. (66) The Silva of North America, Vols. X, XI, XII. Boston, 1897. ScHROEDER, J. (67* Iltilz der Coniferen. Dresden, 1872. ScHRENK, H. VON. (68) The Hardy Catalpa. U. S. Dept. of Agriculture, Bureau of Forestry, Bull. 37, pp. 1-56, 1902. (39) Diseases of the Red Cedar. U. S. Dept. of Agriculture, Div. of Pathol- ogy and Physiology, Bull. 21, pp. 1-21, 1900 (Plates I-VII). LITERATURE 365 Scorr D. H. (70) The Anatomical Charac.en, presented !,;■ ,he Peduncle of Cycadacea^. Ann. Hot., XI, 399-419, 18.S7. (il) Studies in Fossil Botany. London, 1900 WA.ri'^ZuT'^ll^T""-'^'^-- <"> I^-"-" of Plan... Ix,ndon,,897. Ward, Lester F^ (T8 Status of the Me.sozoic Floras of the United Stat . 20th Ann. Kept. U. S. Geol. Surv.. Part 11, 4.8-4.., .898-.i-99. We;« ?^r"r,«';- r^ '".'"''" ""'' ^°'"' °' -'^ "''•"-*• London, .889. Weiss, G. A. (76) Anatomie der Ptianzen. VVien, 1878 WtLUAMsoN, W^C. (76) On the Structure and A^nities of Some Stems from the Coal Measures. M. Mic. J.;i, II, 66-72. V, ITTSTEIN G C. (77) Organic Constituents of Plants. Translated by Baron F. von Mueller, Melbourne, Australia, 1878 Zeiller, R. (71) EWments de Pala;obotanique. Paris, igov I I t INDEX Abies, 10. 14. SI, 58, 76, 82, 83. 88, 80, 94. '04. 107. iia-128, 138-1SJ, 156, •57. 187. "96. «97. »SJ i amabilu, 1 ij, 115, l»i, 255, j6o, 359; balsamea, 88, 102, 112, 118, 140, 141, .54,258.359; bracteata, 102, 121, 138, 139, 145, 254, 202. 3591 concolor, loa, 106, 121, 128, 129, 138, 139, 145, 254, 263,359; excel8a,88, 359; firma. 121. 138, 130, MS. »54. J64, 359; Fnweri, 58, 1T2, 118, 254, 255, 359; grandis. 58, 102, 105, 121, 255, 261, 359; lasiocarpa, 112, 118, 255, 256, 359; magnifica, «02, 105. 121. 25s. 259, 359; nobilis, 102, 121, 128, 138, 139, 145, 254 262, 359; Veitchii, 112. 118, 255, 257 359 " '' Abietinex. 14, 71, ,,5. ,38, ,4,, ,4, '44. "54. 156 ^ Acer campestre, 26; platanoides, iw rubrum, 25 '' ' Acetic acid, 21 Acid, acetic. 21 ; hydrochloric, 49; sul- phuric, 49, igo /Kcidium elatinum, 140 Aeration, 180 Aerobes, 180 Agaricus, 1 78 ; melleus, 40 Age of trees, relation to j owth rincs 2? Air pump, 22 e> 3 Air, removal from sections, 22 Akamatsu. 327 Alcohol. 22. 40, 55, 56 Algse, 192 Alkali, 166 American A'atiiralht, 15 American yew, 213 Ammonia, 49, 55 Ammoniacal, 182 Anaerobes. 180 Anderson, A. P., 139-141, 148 Angiosperms. 37, 39, 57 Anihne chlonde. 49 Anthracite, 172 Anthrax bacillus, 181 Araragi, 214 '5,6. '97. *03. 204; argilliacola, 61; anzonicum,6i, 204, 207; Bidwillii, 29, 61, 197. ?04. 205. 358; brasiliana. 29; Cunninghamii, 29. 61. 73, 204. ,,.c ,,«. I.-.:..„., . ,&a, 28, Araucaria, 14, 28,29, 50-54, S7-«i, 65- <'7. 70-77. 94. "8, 120, 122, 151, 367 205. 358; Doeringii, 61 ; exceia., i, 29. 53. 61, 204, JOS, 358; Heerii.6i , hugehanum, 61 ; Kobertianum, 61, 62, 73; Schmidianum,6i ; subtile, 61 • virginUnum, 61 ; wurtembergianum." Araucarix, 14 Araucariinex, 14 Araucarioxylon, 61, 62, 65, 70, 72, 151, 156, 204; Edvardianum, 29, 61, 204, 208; Hoppertona;, 204, 208; obscu rum, 204 ; Prosseri. 204. 207 ; Virginia- num. 204, 206 ; Woodworthi, 204, 206 Arbor vitx, 221 Arizona, 192 Ash, 26 Auriferous gravels, 164 Australasia, 4 Australia, 8 Bacilli, 182 Bacillus, 177 ; anthracis. 181 ; anthrax, 181 ; cholera, 181 ; hay, 181 ; sub- tills, 181 ; thermophilus. 181 ; tuber- cle, 181 ; of tuberculosis, 181 Bacteria, 165, 175, ,77, ,80, ,81 Bald cypress, 217 Balm-of-Gilead fir, 258 Balsam. 255; Canada, 21; mountain, 256; she, 255; xylol, 23 Balsam fir, 256, 258, 263; Canada, 258 Bastard cedar, 219 Big tree, 225 Bismarck brown, 23 Black larch. 278 Black pine, 328. 334 Black spruce. 289 Blue spruce, 289 Bordered pits, 19, 21, 33, 39, 46, 59. 77. '03-105. 113, 114, 129, x-^^^ ,52, , '55. '56. '84. '88.353 •*•' ^ Bozeman, 166 Britton. N. L„ 8 Brown coal, 1 72 368 ANATOMY OF THE C.YMNOSPERMS Brown rot, iqo Hull pine, 334, 335, 34J Bunya-Bunya, 205 Calamnpltyi, 154; latumi, 155 Caicificaciop, 171, 173 Calcified, 191 Calcite, 173, 174 Calcium carbonate, 174 Calcium oxalate, 109 California. 16 j California juniper, 166 California nutmeg, 21 1 Campbell, U. H., 25 Canada, 25, 167 Canada baUam, 2 1 Canada balsam fir, 258 Canadian Pacific Railway, 164 Canoe cedar, 231 Carbon, 172, 191, 192 Carbon dioxide, 1 77. .Carbonization, 171, 173 Carbureted hydrogen, 172 Catalpa, 26, 153, 179; hardy, 179 Catalpa sprciosa, 178, 190 Cedar, 249; bastard, 219; canoe, 221 ; ground, 250; incense, 219; Oregon, 2^2; Port Oriford, 232 ; post, 21 9; red, 164, 178, 184, 190, 221, 246; rock, 249; shrubby red, 25 i; stinking, 211; wcritern white, 231 ; white, 319, 231, Cedar pine, 323 Cedar ties, 170 Cell wall, 184, 191 Cells, parenchyma, 60, 79, 85, 88, 89, 93. 100, 105, 115, 116, 128, 131, 135, 151 ; ray, 184, 353; resin, 17, 19, 58, 89, 111-122, 124-129, 134, 138-142, '5>. 353 Cellulose, 4, 48, 163, 166, 172, 179, 181, 189, 190, 191 Celluloxylon primxvum, 192 Census, tenth United States, 4, 7, 8, 162 Chamxcyparis, 229 Chamberlain, C. J., 154 Checkered-barked juniper, 251 Chlorophyll, 177 Cholera bacillus, 181 Classification, 193, 105 Closing membrane, 59 Cloves, oil of, 23 Coal, brown, 172; soft, 172 Coleman, A. "., 164 Colonial pine, 205 Colorado spruce, 289 Combustion, spontaneous, 17a Common juniper, 247 Conflagration, 172 Coniferje, 14, 35, 39, 40, 43. 49, 58, 60, 62, 65, 77, 88-90, 102, 105-107, 112, 129, '17, 148, 155 Coniferales, 6, 7, 11, 1 (, 34, 28, 29, 31, 36. 3^< 44. 57. 58. <>2. 65, 66, 70, '71, 74. 75' 77. 79. oj. 8'J. '02, 105, 108, 109, III, 118, 143. 148. 151, 154-156, • 59. «95. *•» Coniferous wood, 184 Constable, Howard, 6 Coonam, 205 Coorong, 205 Cordaitacea:, 14, 38 Cordaitae, 14 Cordaitales, 14, 28, 29, 31, 36, 57, 58, 83, 105, 106, 109, 154-i^x), 195, 198 Cordaitean, 156 Cordaites, 60, 67, 71-73. 199, 202; aca- dianum, 60, 67, 71-73, 199, 202; an- nulatum, 73, 199, 201 ; Brandlingii, 38, 39. 7,5 ; Clarkei, 61, 73, 198, 200; Tiallii, 199, 202; hamiltonense, 60, 7i. 73. ■99> 200; illinoisense, 73, 199, 301; materiarium, 71, 73, 199, 303; materioide, 73, 199, 30i ; Newberryi, 60, 61,71, 73, 198, 200; ohioense,73, 199, 202; ouangondianum, 73, 199, 201; pennsylvanicum, 198, 199; re- centium, 73, 73, 199, 200 Cork, '72, 191 Coulter. J. M., 154, 155, 160 Cowdie pine, 203 Cretaceous, tu, 305 Cupressinex, 14, 19, 57, 112, 117, 119- 122, 144, 156, 187 Cupressinoxylon, 13. 230 Cupressoxylon, 13, 62, 192, 230, 23S ; arkansanum, 231, 240; Calli, 331, 244; cheyenneiise, 230, 238; colum- bianum, 231, 241 ; comanchense, 330, 239; Dawsoni, 68, 71,76, 231, 240; elongatum, 231, 242; glasgowi, 331, 242 ; macrocarpoides, 230, 23S ; McGeei, 231, 243; pulchellum, 231, 239; Wardi, 231, 241 Cupressus, 10, i' 14, 33, 51, 76, 82, 8^ 87-90, 94, 99, ..J, 105. 107, 115, 145, 144, 14C, 157, 197, 228, 329, 335; arizon'ca, 99, 100, 230, 236, 39; INDEX Covenltna. 99, 100, tyo, »jy, ,5,,. blana. 83, ijo, ij6, 359; macr.Karpa, 70. iJo, jjs. 35<, , nootkatennw, 69, JHJ. "9. JJ3. 359 i obtuia. 229, jjj, 359 i pi»i/era, 71., 86. 100, JJ9 sir, J59; Pygmaa, 8; thyoidea. 9.1, iSJ^ 1 70, (59 '^ "~' Cupnc acelatc. 55 Cutin, 191 fycadac^i, 38, 151, ,55, jfe Cycadales, 14, 155 Cycadean, 155 CycadofiUc... 45, 149, ,5,, ,54_,56, Cycada, 95. 150, 151 Cypreas, 236, 237; bald. 217; decidu- ous, 217; I^w»on'», 232; Monterey, J35; S>"tka, 233; yellow. 233 Cysts. 117, ,24, 128-131, ,34, 136-146, Ciapek. Fr., 190 Dahlonega. (68 nammar. gum. 36 Dammara, 14, 29. 5,. 54, 57 es, 62, 66. 67.70.72-7^82. II9-I22, ,,,, ,56, «S». "97. aoj; au8tralis, s4--6. 62. 65. 66, 203. 358 ^ ■' • Daw-son. Sir J. W.. 208. 214 f,.^2:r\i^' '^' 33- 35. 37. 39. 44. 64. 6^,. 88. 104, 129. ,30. 141, ,42, 14". 170 De Vries, M., 152 I>e?aYj 163, 175-192 Deciduous cypress, 2 1 7 Desiccation. 181 Devonian. 11, 171, 17J Digger pine, 342 Don River. 214 Don valley. 164-769 Douglas fir, 31, 32, 52, ,66. ,83, 272- 274 •'• ' Drought, 25, 26 Dry rot. 178, 182. 185 Dudley P. H., ,70, ,7,. .;8, ,83 Durability, ,62-174 Kichler, A E., 44, ,09, ,12, 115, 1,6, 156 Elder, 26 Endophytic, 177 Kngineering Building, MacDonald, iSi Englemann's spruce, 286 Kngler, A., 7 Knglish maple, 26 Knzymes. 163, 1S8. ,89 Eocene. 15, 369 Ephedra, <"•<) Kpiphytic. 177 Kp.theliun.. y.S. 115-1,7, 124-136, 140, Ether, 55 r.usporangiate femi, ,49, ,j. Facultative parasite, ,78 Facultative saprophyte, it8 FaguH sylvatica. 48 Ferguson, Margaret C, 154 Fernow. B, E., 8. ,0, 1, I'erns. eusporangiate, ,49, |i| Fir. Balmof (Jilead. 258; balsam. 256, 2S». 263: DouglM. 3,, 32, 52. 166, i»3. 272-274; red, 259, 262; silver. 262; white. 260, 261, 263; yellow. Fires, forest. 25, ,72 Fission fungi, ,75 Flad, Henry, 6 Florida, 25 Food, i86-)88 Forests, petrified, 192 Fossil wood, 172 Fossils. 162-174, '9' Foxtail pine, 308, 309 Frost. 25. 26 Fujimatsu, 280 Fundamental tissue. 148, 149. 152 Fungi. ,65, 166, 176, ,77. ,79, ,g,-,84, 189. ,9,; fission, 175 Fungus, ,77, 185, 187, ,88 Fusifc-m rays. 44, 96, ,08, 130, 353 Gases, 172 Georgia, 168 Germination, 182 Ginger pine, 232 Gingko, 14, 28, ;i, 5, 65, -4, 76, 82, 9<, 05, 10.,, 119, (30. I ',, ,96, 209; .ioba, no, i^ 158: axilla, 200 Gingk.iace.T, 14 Gingkoales, 14. ;S, j6, 58. .. 66, 70. 74, 83, 106. 109, i.4-i#ei ,05, 209 "^ Gingkoinea-, 14 Gland, resir, 140 Glucose. 190 Gray pine, 3:1 (Jround cedar, 250 Ground hemlock, 213 Gro»;th, cessation of, 30; ecceni itj of. 28; secondary. 55. 70, ,04, •«•- ^ "af>-. 35. 38 Growth rings. 24, 32, 40, ,,7 138-140 ; eccentricity of, 2S I h ) i I '' 1 370 ANATOMY OF THE GYMNOSPERMS ■ ife, i ^^Sr (ium damtn»r, 56 (lymnonpeim*, 13, 33, 36, 38, 57, 58, 60, ISO. 153, 154-156 (lymnosporanglttm cwvarizlomte, 141 Hackmatack, tjA lladromal, 190 Hematoxylin, Delafiekl'ii, 21 Hard pine, 30, 71, Hi, 85, 87, 89, 100, 10^, 106, 108, IJ4, 318 Hartig, Cieorg Ludwtg, 6 ilartig, H., 6, a6 lUrtig, TheiKlur, 6, l8a lUurloria, 177, 186 Hisartwood, 179 Hemlock, 178, a66, 368, J75; ground, 213; mountain, 269; western, 270 Hemlock ties, 170 Hcterangium, 1541 Grievii, 73 Hiba, 215 Hickory pine, 309, 337 HImekomatsu, 316 Hinoki, 334 Hoop pine, 205 Horse-chestnut, 26 Idioblasts, crystallogenous, 109-111 Inrense cedar, 219 Inliltration, 192 Injuries, 25, 26 Insects, 21. 36 Intercellular spaces, 46, 127 Intercellular substance, 46 189 Interglacial, 11, 165 Iodine, 49 Iramomi, 287 Iron, sulphide of, 174 Jack, J. C, 8, 10 jack pine, 331 japan, 4, 8 Jeffrey, E. C, 8, 13, 20, 96, 102, 108, 122, g9-lS2' "54. "64 jersey pme, 338 Jesup, M. K., 8 Juniper, 248-253; California, 166; checkered-barked, 251; common, 247 Juniperus, 12, 14, 28, 32, 51, 52,82-84, 87, 88, 94, 99, 100, 105-107, 1 18, 1 19, 141, 144, 146, 196, 244; barbadensis, 8; cahfomica, 165, 245. 248, 359; communis, 12, 140, J45, 250, 359; ci'ii/ugens, 52 (see j. sabinoides) ; mono.iperma, 245, 252, 359; nana, 12, 88, 245, 251, 359; occidentalis, 245- 25". 359 i rigida, 12, 245, 247, 359; sabma, 52, 245, 251, 359; sabi- noides, 245, 249, 359; scopulorum, 8 ; utahensU, 345. 349, 359 ; virgini' ana, 5, 50, 164, 165, 178, 184, 190, »45. H5, 276; americana, 34, 40, 41, 43. 63, 66, 68, 71, 75, 77. 86. 132, 168, >77. '78. 360; leptolepis, 66, 277. 280 ; 360 ; Lyallii. 50. 277. 380. 360 ; occidentalis, 77. 132, 143, 276, 377, i^^ . Lavrson's cypress. 332 Leaf buds, 36 I^ntinus lepideus, 170 I^pidodenaron selaginoidea, 90 Libocedrus, 14, 19. 49. 51, 76, 86, 87, 9^. 95. "OS. ii7-"»o, 144, 146, 196, 319; decurrens, 50, 319, 358 Lignification. 48 Lignified, 163 Lignilied wail, 190 Lignin, 48, 173 Lignite Tertiary, 76, 108 Lignites, 173 Live nak, 273 Ix>blolly pine, 343 Ix>dge-pole pine. 328 Long-leaved pine. ,144 Lyginodendron. 154 Mac Donald Engineering Building. 183 McGill College. 169 McGill University. 183 Maceration, 5, 69 ; Schulze't, 49 Macoun, John, 214 Maidenhair tree, 309 Maisonneuve, 170 Maki, 216 Mangin's reaction, 49, 190 Manitoba, 214 Maple, English, 26; Norway, 159, 160 Marsh pine, 320 Maxwell, E. J., 8 Medullary rays. 18. 20, 33, 39, 53, 56. 78-108, 130.135, 141, 143, 151, 152. 186, 187 Membrane, closing or pit, 59 Meristematic, 140 INDEX Mtruliu* tachrymaiM, lyS, iSj Mkrotnma, j} Mlnaralization, 17J Miocene, 141, 164, I I Miiwionarieii, Franciscan, ji Momi, 264 Montana, 166, 214 Monterey cjrprciii, 235 Monterey pine, 341 Montreal, 25, 26, 169, 170 Moreton Hay pine, 205 Mountain hemloik, 169 Mountain larch, 280 Mounting ncctionii, 2j Mucilage canaU, 149, 151 Mueller, Harop K. von, i Muller, N. J. C, 6 Muro, 247 Mycelia, 164-169, 176, 184- > Myxtic Lake, 166 Natural Hiatory Society of Montreal, 170 AatUrlichtH PflanztH/amilitii, 7 Nedzuko, 122 Nematophycus, 173; crassus, 192; ■•"({ani, 192 Norulinger, II., 6 Norfolk Island pine, 205 North America, 4 ; silva of, 7, 8 Norway maple, 159, 160 Norway pine, 325 Nut pine, ^05-307, 310 Nutmeg, California, 211 Oak, live, 273; red, 273; white, z-ii. Oblipite parasite, 178 Obli . • > saprophyte, 178 Oil .)ves, 23 Oils, d, 55 Old. .w pine, 343 < -regon, igi <^regon cedar, 232 ysn-undites skidegatensis, 171 OTr.hi. 288 ^^ Oxidation, 163, 177 Otygen, 172, 179, iSo, 191 Paleobotany, 151 Panama Railway, 170 Parasites, 140, 141, 177; facultative, 178 Parenchyma ce!U., Oo, 7,,, 85, 88, 89, 93, 100, 105, 115, llO, 128, I If, I7C, 151 ^^ Parenchyma tissue, f(|2 Parenchyma tracheids, 17, 33, 35, uj, 117. «20, 124-136, 140 37 » 'V'ri^r* ' '""*■ '^' "■ "' ***• '** Parenih)mato.,. . ii, js Pathological, <,8 I'atton •prii'-- , .n,) Peat, 17' Pectic aci 4.y Pectin, 47 Pen; Mow, I) P., jj. ,0,. ,„, ,4^. „, Penitillium glaucurn, i8. Peridermium pini, 140 Permian, 192 Petrified forests, 192 Phosphureted hydrogen, 172 Photography, 23 Phylogeny, 58, ,18, 138-153, ,54.,6, Phylum, 148, 155 Picea. 10, II. 14. 5, 76,78,82,83.87. »9. 90, 9V 94. '/>-9». 100, 106, 107, 112, 11(^.121,128,130.133. 134. ,38- 146. 156, 167. 187, 195, 281; afiw, '33- '3-1, 167, 282, 285, 360; bicolor. 66, 282, 288, 360; Hreweriana, 283. 360; Engelmanni. 282, 286. 160: jesoensis. 283. 287. 36c; nigra, 131. •34. •67. 169. 232. 289. 360: polita. 106, 282, 287,360; pungens, 134, ^82, J8<;, 360; rubra, 283, 284,360; sit. chensu-, 134, 281. 290, 360 Pierce, j. C. 148 Pine, black. 328. 334; bull. 334, 335. 34* ; cedar, 3.13 ; colonial, 205 ; towdie, 203; digger, 342; foxtail, 308, 309; ginger, 232 ; gray, 321 ; hard, -o, 71, 82, 85, 87, 8g, 100, 103, 106, 108. 134, 318; hickory, 309, 337; hoop, 205; Jack, 321: ersey, 338; knob-cone, 331 ; loblo jr, 343; long-leaved, 344; lodge-pole, 328; marsh, 320; Monte- rey, 341; Moreton Bay, 205; Nor- folk Island, 205 ; Norway, 325 ; nut, 30S-J07. 3'°: old field, 343; pitch, 3'8. 330; pond, 320; prickle30. 353: medullary. 18, 20, 33, 3<). S3. 56. 78-108, 130, 135, 141, 143. 151, 152, 186, 187; tracheids. 33,35, 85. 88-93, 'OS, 105-108, 115, ^53 Red cedar, 164, 178, 184, 190, 221, 241') Red fir, 259, 262 Red oak, 273 Red pine, 170, 325 Red spruce, 284 Redpath Museum, l6<; Redwood, 224 Reservoirs, secretory, 58, 1 23, 1 28, 1 30, 136- MS INDEX 373 Resin canals. Ste Resin passages Kesin cells, 17, 19, 58,89, 111-122, 124- 129. 134. 138-142. IS". 353 Resm cysts, 17, 19. 58, 1 21-124, "3«- 146, 150, 152 Resin flux, 140 Resin gland, 140 Resin passages, 17, 18, 19, 20, 44, 58, 78, 79, 89, 98, 108, 111-155, '87, 353 Resinous tracheids, 34, 53-58, 120, 123 Rhizopus nigricans, 183 Rhus typhina, 26 Rock cedar, 249 Rocky Mountains, 214 Rot, brown, 190; dry, 178, 182, 185; soft, 190; white, 190 Ruthenium, red, 47, 49 Salicacex, 153 Salisburia, 209 Sambucus racemosa, 26 Sand pine, 318 Sanio's bands, 53, 55 Saprophyte, 177; facultative, 178; obligate, 178 Sargent, C. S., 4, 7, 8, 13, 162 Savin, 211, 246 Sawara, 233 Scalariform, 38 Scarborough period, 167 Schizogenously, 46, 116 Schizomycetes, 175 Schrenk, H. von, 163, 178, 179, 190 Schulze's maceration, 49 Scott, D. H., 155, 160 Scrub pine, 318, 321, 322, 338 Secondary growth, 70, 104, 189 Secondary wood, 34, 155 Secretory reservoirs, 58, 123, 128, 130, 136, 145 Sections, mounting, 22 ; preparation of, 21; radial, 18; removal of air from, 22; tangential, iS, no, in; trans- verse, 17 Sequoia, 10, 13, 14, 19, 25, 51, 52, 62, 68, 75-77. 82-87, 94. 99. 100, 107, 112-123, 127-129, 141, 143-152, 157, 196, 223; Burgessii, 20, 96, 108, 126, 142, 151, 224, 226; gigantea, 52, 65- 67, 84, 86, 139-144, 152, 157, 223, 225. 358; I^ngsdorfii, 142, 144, 324. 226; magnifica, 233, 226; I'enhal- lowii, 96, 102, 108, 126, 140-144, 148, 164, 224, 228; sempervirens, 52, 86, 94, 113, 114, 117, 121-127, I4«-I44, 148,157,195,233,224,358 Mie balsam, 255 Shirabe, 257 Short-leaved pine, 324 Shrubby red cedar, 251 Sierra Nevada Mountains, 164 .Sigillaria, 75 Silica, 192 ^ili'^ffi""''?;5. '67. 171. 173. 174 Sihcified, 166, 172, 191 Silurian, 171 Silva of North America, 7, 8 Silver fir, 262 Sitka cypress, 233 Sitka spruce, 290 Slash pine, 345 Sodium carbonate, 21 Soft coal, 172 Soft rot, 190 Soledad pine, 332 Southern pine, 344 Spiral tracheids, 17, 21, 33-45, 152, 353 Spirillum cholera-asiatica-, 181 Spontaneous combustion, 172 Spores, 176, 181, 182, 184 Spring tracheid.s, 52, 86, 87 Spring wood, 17, 31, 30, 33, 49, 50, 58, 00,69, «04. no, 117, 127, 128, 131- '34. 139-M2, 166, 184, 273 Spruce, black, 289; blue, 2S9; Colo- rado, 289; Engelmann's, 286; I'at ton, 369; pine, 318, 333, 32S; red, 284 ; Sitka, 2(>o ; tideland, 290 ; weep- ing, 283 ; white, 285, 286 Staining, 22 Starch, 179 Stigmaria, 95 Stinking cedar, 211 Stratification, 47 Striation, 47, 69, 191 Sugar, 179 Sugar pine, 311 Sugi, 316 Sulphide of iron, 174 Sulphuric acid, 49, 190 Sumac, 26 Summer tracheids, 43, 52, 86 Summer wood, 17, 21, 31, 32, 39, 49, 50, 58, 68, 69, 92, 104, no, 117, 118, 121, 128, 131, 132, 134, 138-145, 166, ^ '84. 273. 353 Swamp pme, 345 Systematic, 193, 195 Table mountain pine, 337 Tamarack, 377, 378, 280 Tangential sections, 18, 70, no, ni Tangential walls, 65, 66, 75, 129, 136 Taxacea-, 14, 40, 66, 74, 77, 105, 106, n2 Taxodiinex, 14, 19, 156 374 ANATOMY OF THE GYMNOSPERMS Taxodium, lo, 14, 19, 51, 76,82,84,87, 1 12-122, 144, 196, 217; distichum, 31, 81, 87, 217 ; laramianum, 217, 218 Taxus, 9, 14, 28, ,)2, 34, 37, 40, 4 1, 44, 47, 69,76,99, 112, 119, 144, 148, 151, 184. 196, 212; brevifolia, 42,94, 213, 214, 358; canadensis, 42, 50, 51, 212, 213, 358 ; cuspidata, 42, 99, 213, 214, 358 ; floridana, 42, 74, 213, 358 Temperature, 181, 182 ; maximum, 182; minimum, 181 ; optimum, 181 Tenth census of the United States, 4, 7.8 Tertiary, 76, 164 ; lignite, 76, 108 Tertiary wall, 36, 40, 47, 190 Thiselton-Dyer, Sir W. T., 8 Thujopsis, 14, 51, 76, 82, 117-119, 144, 146, 197, 215; dolabrata, 215, 358 Thuya, 10, 14, 32, 51, 76, 82, 89, 99, 107, 117, 119, 122, 144, 146,157, 197, 220; gigantea, 82, 88, 99, 220, 221, 358; -iponica, 88, 220, 222, 358; occidentalis, 220, 221, 358 Thyloses, 79, 126, 129, 131-137, 143, 353 Tideland spruce, 290 Ties, cedar, 170; hemlock, 170 Tissue, fundamental, 148, 149, 152; wood, 172, 186 Tissues, lignified, 163, 189 T6hi, 287 Toronto, 164, 167, 214 Torreya, 9, 14, 32, 34, 37, 40-47, ct, S*> 09. 75' 99. H2. 119. '44. 151. 184, 196, 210; califomica, 41, 43, 74, 210, 211, 358; nucifera, 41, 66, 74, 99, 210, 212, 358; taxifolia, 41, 49, 66, 69. 7«. 74> 77. 2«o. 2". 358 Tracheae, 39 Tracheids, 17, 21, 30, 33-58, 140, 141, 152, 169, 184, 186, 188; parenchyma, «7. 33. 35. «i5-"7. 120, 124-136, 140; pitted, 17, 33, 34, 45-53; ray, 33. 35. 85. 88-93, '02, 105-108, 115; resin, 34, 53-58, 120, 122; spiral, 17, 21. 33-45. «52. 353! spring, 52, 86, 87; summer, 43, 52, 86; wood, 30, 34, 88, 105, 1 10, 1 15, 127, 128, 132, 136 Trametes pini, 190 Transition, 31 ; zone, 19, 152 Trinsverse sections, 17 Ti umatic, 141, 148 Ti es, age of, 25 Tsuga, 10, 14, 51, 76, 83, 88, 90, 93, 107, 114, 116, 118-123,128, 129, 139- 148, 156, 197, 265, 267; canadensis, 63. 71. 77. «70. >78, 265, 266, 359; caroliniana, 127, 129, 138, 145, 266, 359; Mcrtensiana, 128, 129, 132, i^S, 142, 145, 195, 265, 270, 360; Pat toniana, 266, 269, 359 ; Sieboldii, 50, 266, 267, 3S9 Tubercle bacillus, 181 Tubeuf, K. F. von, 6, 140, 190 Tumor, 148 Tyrolean lar:!), 26 Vallisneria spiralis, 165 Vascular plants, 192 Walchia, 156 Wall, cell, 184 ; lignified. 190; primary, 46, 49. 59. 189, 190; radial, 60, 136; secondary, 36, 40, 47, 49, 60, 69, 169; tertiary, 36, ao, 47, 190; tangential, 65, 66, 75, I.J, 136 Wanning, E., 181 Weeping spruce, 283 Weiss, G. A., 48 Western hemlock, 270 Western white cedar, 22 1 Western yew, 214 Weymouth pine, 315 White cedar, 219, 221, 232 White fir, 260, 261, 263 White oak, 273 White pine, 162, 312-315, 317, 323 White rot, 190 White spruce, 285, 286 Wittstein, G. C, 55 Wood, coniferous, 184; durability of, 162-174 i fossil, 172 ; preservation of, 162, 174; secondary, 34, 155; spring, 17, 21, 30, 32, 49, 50, 58, 66, 6q, 104, no, 117, 127,128, 131, 134, 139-142, 166, 184, 273 ; summer, 17, 21, 31, 32, 39. 49. SO. 58. 68, 69, 92, 104, no, 117, 1 18, 121, 128, 131, 132, 134, 138-145, 166, 184, 273, 353 Wood parenchyma, 17, 53, 55, 58, 109 112, 122 Wood parenchyma tracheids, 35 Wood tissue, 172, 186 Wood tracheids, 30, 34, 88, 105, 1 10, 115, 127, 128, 132, 136 Xylem, 149 Xylol balsam, 23 Yellow cypress, 233 Yellow fir, 272 Yellow pine, 170, 324, 329, 333, 335, 345 Yew, 214; American, 21?: western, 214 Zea, 35 PLATES PLAT. .. PS.UOOTSUO. Douo^sn ^Vansverse section showing the Structure of the fine-grained wood, x 41.2 Plate 2. Torreya taxifolia. Transverse s«-tmn =k • of growth nngs in an ^rl^eTl^nr x^f '^"^'^^""'^'^ I?' Platr 3. foRDAiTES Hrandlingii. Radial section of the transition zone next the pith, showing the protoxylem to be wholly composed of spiral tracheids. X IS3-4 Plate 4. Cordaites Brandlingii. Radial section of ' transition zone imme- diately external to the preceding, and showing the spirals of the tracheids passing into scalariform structure, x 153.4 Plate s. Cordaites BRAvniisim boj:..i forced. n.u..Ueria.e boSd pits x S" '"■"'"" '"'" ™''""=^'" I'l.ATE 7. CoRDAlTKS ACADIANi'M. Radial section showirijj; the completed bor- dered pits with a primitive arrangement, x 180 Plates, (ordaitf.s Nf.wberryi. Radial section showing the peculiar group- ing of the bordered pits. X 180 } Plate 9. rrrRF.ssrs n-.m.tkatf.nsis. Radial section showing the longituclinal distribution of fungus mycelia in the tracheids of the wood, x .50 l.n Platk 10. Cui-iKssus NooTKATENSi: Radial Section .iu.wing the transverse .s.r,bu.,on of fungus .yce.ia in the tracheids of the wood, and their relli to the trachetd walls, x 150 •i il PIJ4TF. II. PsEUDOTSUGA MiocENA. Radial section showing the effects of flecav in lireaking up the nuljgtance of the cell wall along the lines of »t iution. X 137-8 Plate 12. Cordaites materiakium. Transverse section showing the absence of growth rings, the character of the tracheids, and the distribution of resinous tracheids near the medullary rays. X 40.9 Plate 13. Cordaitf.b mateharium. Tangential section nhowlng the character of the ordinary medullary rays which are sometimes two-seriate, x 40.9 Plate 14. Dammaea austhaiis. TransversesiectionHhowing the dearly defined growth ring and its summer wood, and the distribution of resin cells near the medullary rays, x 46.8 m Platk ij. Dam^'ara At'sTRALls. Tangential section xhowing the character of the nirilullarv ay> ^nd the occurreno. and location of plate:* of resin, x Si ^ PlJ»TE i6. Araucaria glauca. Transverse section showing the general chai- acter of the structure, the absence of growth rings, and the distribution of resinous tracheids. X 46.S i ^itimiiiiMi i'lATK 17. A.AI CAEIA 01.AI cA. Tangential section showing the character of the medullary ray*, x 46.8 PIATE ,8. r.lNOKo RiroBA. Transverse .Pcnon .howing the dcvelopn.^.U .,1 a -strong growth rmg. and the occurrence of crystals as indicated by dark spots in line with the tracheids. x 46.8 \ Pl.ATK i<). CilNGKO BILOBA. Tangential section showing the character of the very low medullary rays. X 52 if' W.'l till ill liilWWMA Pl.ATK .'O. ToRRFVA TAXIFOMA. Transverse section showing the Very thin and open summer wood, x 46.8 Pl-ATK 21. ToRREYA TAXIKOLIA. Tangential section showing the character of the medullary rays, x 52 Plate 21. Taxus tusnUAiA. Transverse section showing the rather dense structure of the thin summer wood, x 46.8 If wk Platk 2J. Taxus crspiDATA. Tangential section showing the character of the very narrow and rather high medullary rays, x 52 Plj^TE 24. Thl'Jopsis dolabrata. Transverse section showing the narrow growth rings, the thin summer wood, and the distribution of resi:i cells in the spring wood, x 46.8 Plate 25. Thujopsis noiABRATA. T of the low rays in the ' i angential section showing the character pring wood, x 52 Plate -6. fKYrroMERiA japoNica. Transverse section showing the very dense summer wood and the distribution of resin cells, x 46.8 II lij f»"' Plate 27. Cryptomf.ria japonica. Tangential section showing the cliaracter of the iow rays in the spring wood, x 52 Pl^TE 28. PoDOCAKi'ts MACKufllYl-LA. Transverse Section shutting the general structure and the distribution of the numerous resin cell-s. x 46.8 Pl.\te 29. PonocARPUs MACROPHYLLA. Tangential section showing the struc- ture and very resinous character of the medullary rays, in the region hetween the spring and summer »c;ds. x 46.8 Plate jo. Taxodium distichum. Transverse section showing a double zone of summer wood a:id the distribution of resin cells in tangential rows, x 4C.8 Pi.ATK 31. Taxodu'M nisTiriii'M. Tangential section showing tlie character of the medullary ray.s x 46.8 Platk 32. LlBOCEDRUS DECURRENS. Transverse section showing the dense summer wood and the distribution of the resin cells, x 46.8 Platf V3. LiBOCEDRirs DKCURRENS. Tangential section showing the character of the rather broad medullary rays and the occurrence of re-sin. x 64 iiiiiiiilijlliiipwiiiililiiiiiii Plate 34. Thuya occidentalis. Transverse section showing the narrow cX xTs "^ '''" """"" *°°'' '""' '""^ •1-'"'^'"'- of the r^:: fi Plate 35. TiirvA ornnF.NTAl.ls. Tangential section showing the very narrow medullary rays with narrowly oblong cells, taken from the spring wood. X 64 Platk ^6. Seqi'OIA sempervirens. Transverse section showing the very large tracheids of the spring wood with thin walls, the rather dense summer wood with a somewhat abrupt transition from the spring wood, the scaUering dis- tribution of the resin cells, and the occurrence of resin sacs in the initial layer of the spring wood. X 46.8 1 Plate 37. Skqi-ou skmpervirf.ns. Tangential nection from the spring wood showing the very broad medullary ray.s, the celU of which are equal and uniform, x 64 Plate 38. CrpREssirs Goveniana. Transverse section showing the very thir summer wood and the distribution of the resin cells, x 46.S Platk 39. CuPKESSt's GovKNiANA. Tangential section showing the very liroad itnd low medullary rays, x ji -» Plate 40. Ji'NiPF.Rt's californica. Transverse section showing the char- acter of the growth rings and the distribution of the resin cells, x 46.8 Plate spring Pl-ATF )3, .MslFS NOBu.is. Transverse section showiilg the otcurreiKe , if resin canals and the distribution of scattering resin ceVi on the outer face of the summer wood, x 39.2 I'LATK 4J. AbiKS Nubii.is. Tangential xntinn xhowing the character nf the medullary rayi*. x 46.8 Flatk 44. TsuGA Pattoniana. Transverse section showing the character of the summer wood and the distribution uf the resin cells on the outer face of the growth ring, x 46.8 I'LATK 4S. TsioA Pattonian*. Tangenlial se